diff --git a/src/tiled/documentmanager.cpp b/src/tiled/documentmanager.cpp
index 1e17e41a7a..05c425c7ef 100644
--- a/src/tiled/documentmanager.cpp
+++ b/src/tiled/documentmanager.cpp
@@ -1062,20 +1062,17 @@ void DocumentManager::tabContextMenuRequested(const QPoint &pos)
 
     menu.addSeparator();
 
-    QAction *closeTab = menu.addAction(tr("Close"));
-    closeTab->setIcon(QIcon(QStringLiteral(":/images/16/window-close.png")));
-    Utils::setThemeIcon(closeTab, "window-close");
-    connect(closeTab, &QAction::triggered, [this, index] {
+    QAction *closeTab = menu.addAction(tr("Close"), [this, index] {
         documentCloseRequested(index);
     });
+    closeTab->setIcon(QIcon(QStringLiteral(":/images/16/window-close.png")));
+    Utils::setThemeIcon(closeTab, "window-close");
 
-    QAction *closeOtherTabs = menu.addAction(tr("Close Other Tabs"));
-    connect(closeOtherTabs, &QAction::triggered, [this, index] {
+    menu.addAction(tr("Close Other Tabs"), [this, index] {
         closeOtherDocuments(index);
     });
 
-    QAction *closeTabsToRight = menu.addAction(tr("Close Tabs to the Right"));
-    connect(closeTabsToRight, &QAction::triggered, [this, index] {
+    menu.addAction(tr("Close Tabs to the Right"), [this, index] {
         closeDocumentsToRight(index);
     });
 
diff --git a/src/tiled/fileedit.cpp b/src/tiled/fileedit.cpp
index 171af383e4..e8f65daffa 100644
--- a/src/tiled/fileedit.cpp
+++ b/src/tiled/fileedit.cpp
@@ -45,6 +45,7 @@ FileEdit::FileEdit(QWidget *parent)
     QToolButton *button = new QToolButton(this);
     button->setText(QLatin1String("..."));
     button->setAutoRaise(true);
+    button->setToolTip(tr("Choose"));
     layout->addWidget(mLineEdit);
     layout->addWidget(button);
 
@@ -111,23 +112,40 @@ void FileEdit::validate()
     const QUrl url(fileUrl());
 
     QColor textColor = mOkTextColor;
-    if (url.isLocalFile() && !QFile::exists(url.toLocalFile()))
-        textColor = mErrorTextColor;
+    if (url.isLocalFile()) {
+        const QString localFile = url.toLocalFile();
+        if (!QFile::exists(localFile) || (mIsDirectory && !QFileInfo(localFile).isDir()))
+            textColor = mErrorTextColor;
+    }
 
     QPalette palette = mLineEdit->palette();
-    palette.setColor(QPalette::Active, QPalette::Text, textColor);
+    palette.setColor(QPalette::Text, textColor);
     mLineEdit->setPalette(palette);
 }
 
 void FileEdit::buttonClicked()
 {
-    QUrl url = QFileDialog::getOpenFileUrl(window(),
-                                           tr("Choose a File"),
-                                           fileUrl(),
-                                           mFilter);
-    if (url.isEmpty())
+    QUrl url;
+
+    if (mIsDirectory) {
+        url = QFileDialog::getExistingDirectoryUrl(window(),
+                                                   tr("Choose a Folder"),
+                                                   fileUrl());
+    } else {
+        url = QFileDialog::getOpenFileUrl(window(),
+                                          tr("Choose a File"),
+                                          fileUrl(),
+                                          mFilter);
+    }
+
+    if (url.isEmpty()) {
+        validate();
         return;
+    }
+
     setFileUrl(url);
+    validate(); // validate even if url didn't change, since directory may have been created
+
     emit fileUrlChanged(url);
 }
 
diff --git a/src/tiled/fileedit.h b/src/tiled/fileedit.h
index 7044677c07..44565e2c0b 100644
--- a/src/tiled/fileedit.h
+++ b/src/tiled/fileedit.h
@@ -44,6 +44,9 @@ class FileEdit : public QWidget
     void setFilter(const QString &filter) { mFilter = filter; }
     QString filter() const { return mFilter; }
 
+    void setIsDirectory(bool isDirectory);
+    bool isDirectory() const;
+
 signals:
     void fileUrlChanged(const QUrl &url);
 
@@ -60,8 +63,20 @@ class FileEdit : public QWidget
 
     QLineEdit *mLineEdit;
     QString mFilter;
+    bool mIsDirectory = false;
     QColor mOkTextColor;
     QColor mErrorTextColor;
 };
 
+
+inline void FileEdit::setIsDirectory(bool isDirectory)
+{
+    mIsDirectory = isDirectory;
+}
+
+inline bool FileEdit::isDirectory() const
+{
+    return mIsDirectory;
+}
+
 } // namespace Tiled
diff --git a/src/tiled/main.cpp b/src/tiled/main.cpp
index 8504ee16bb..dcf56dfafc 100644
--- a/src/tiled/main.cpp
+++ b/src/tiled/main.cpp
@@ -494,7 +494,7 @@ int main(int argc, char *argv[])
     QObject::connect(&a, &TiledApplication::fileOpenRequest,
                      &w, [&] (const QString &file) { w.openFile(file); });
 
-    initializePluginsAndExtensions();
+    PluginManager::instance()->loadPlugins();
 
     w.initializeSession();
 
diff --git a/src/tiled/mainwindow.cpp b/src/tiled/mainwindow.cpp
index 5279ec2266..7647fd8942 100644
--- a/src/tiled/mainwindow.cpp
+++ b/src/tiled/mainwindow.cpp
@@ -60,7 +60,9 @@
 #include "objecttypeseditor.h"
 #include "offsetmapdialog.h"
 #include "projectdock.h"
+#include "projectpropertiesdialog.h"
 #include "resizedialog.h"
+#include "scriptmanager.h"
 #include "templatesdock.h"
 #include "terrain.h"
 #include "tile.h"
@@ -274,10 +276,10 @@ MainWindow::MainWindow(QWidget *parent, Qt::WindowFlags flags)
     ActionManager::registerAction(mUi->actionLabelsForAllObjects, "LabelsForAllObjects");
     ActionManager::registerAction(mUi->actionLabelsForSelectedObjects, "LabelsForSelectedObjects");
     ActionManager::registerAction(mUi->actionLoadWorld, "LoadWorld");
-    ActionManager::registerAction(mUi->actionNewWorld, "NewWorld");
     ActionManager::registerAction(mUi->actionMapProperties, "MapProperties");
     ActionManager::registerAction(mUi->actionNewMap, "NewMap");
     ActionManager::registerAction(mUi->actionNewTileset, "NewTileset");
+    ActionManager::registerAction(mUi->actionNewWorld, "NewWorld");
     ActionManager::registerAction(mUi->actionNoLabels, "NoLabels");
     ActionManager::registerAction(mUi->actionOffsetMap, "OffsetMap");
     ActionManager::registerAction(mUi->actionOpen, "Open");
@@ -285,6 +287,7 @@ MainWindow::MainWindow(QWidget *parent, Qt::WindowFlags flags)
     ActionManager::registerAction(mUi->actionPaste, "Paste");
     ActionManager::registerAction(mUi->actionPasteInPlace, "PasteInPlace");
     ActionManager::registerAction(mUi->actionPreferences, "Preferences");
+    ActionManager::registerAction(mUi->actionProjectProperties, "ProjectProperties");
     ActionManager::registerAction(mUi->actionQuit, "Quit");
     ActionManager::registerAction(mUi->actionRefreshProjectFolders, "RefreshProjectFolders");
     ActionManager::registerAction(mUi->actionReload, "Reload");
@@ -655,6 +658,7 @@ MainWindow::MainWindow(QWidget *parent, Qt::WindowFlags flags)
     connect(mUi->actionAddFolderToProject, &QAction::triggered, mProjectDock, &ProjectDock::addFolderToProject);
     connect(mUi->actionRefreshProjectFolders, &QAction::triggered, mProjectDock, &ProjectDock::refreshProjectFolders);
     connect(mUi->actionClearRecentProjects, &QAction::triggered, preferences, &Preferences::clearRecentProjects);
+    connect(mUi->actionProjectProperties, &QAction::triggered, this, &MainWindow::projectProperties);
 
     connect(mUi->actionDocumentation, &QAction::triggered, this, &MainWindow::openDocumentation);
     connect(mUi->actionForum, &QAction::triggered, this, &MainWindow::openForum);
@@ -700,6 +704,7 @@ MainWindow::MainWindow(QWidget *parent, Qt::WindowFlags flags)
     setThemeIcon(mUi->actionCloseProject, "window-close");
     setThemeIcon(mUi->actionAddFolderToProject, "folder-new");
     setThemeIcon(mUi->actionRefreshProjectFolders, "view-refresh");
+    setThemeIcon(mUi->actionProjectProperties, "document-properties");
     setThemeIcon(mUi->actionDocumentation, "help-contents");
     setThemeIcon(mUi->actionAbout, "help-about");
 
@@ -909,10 +914,7 @@ void MainWindow::newMap()
 
 void MainWindow::initializeSession()
 {
-    auto prefs = Preferences::instance();
-    if (!prefs->restoreSessionOnStartup())
-        return;
-
+    const auto prefs = Preferences::instance();
     const auto &session = prefs->session();
 
     // Restore associated project if applicable
@@ -922,7 +924,13 @@ void MainWindow::initializeSession()
         updateWindowTitle();
     }
 
-    restoreSession();
+    // Script manager initialization is delayed until after the project has
+    // been loaded, to avoid immediately having to reset the engine again after
+    // adding the project's extension path.
+    ScriptManager::instance().initialize();
+
+    if (prefs->restoreSessionOnStartup())
+        restoreSession();
 }
 
 bool MainWindow::openFile(const QString &fileName, FileFormat *fileFormat)
@@ -956,6 +964,11 @@ bool MainWindow::openFile(const QString &fileName, FileFormat *fileFormat)
     return true;
 }
 
+Project &MainWindow::project() const
+{
+    return mProjectDock->project();
+}
+
 void MainWindow::openFileDialog()
 {
     SessionOption<QString> lastUsedOpenFilter { "file.lastUsedOpenFilter" };
@@ -1333,6 +1346,8 @@ void MainWindow::switchProject(Project project)
     mProjectDock->setProject(std::move(project));
     prefs->switchSession(std::move(session));
 
+    ScriptManager::instance().refreshExtensionsPaths();
+
     restoreSession();
     updateWindowTitle();
     updateActions();
@@ -1355,6 +1370,12 @@ void MainWindow::restoreSession()
     mProjectDock->setExpandedPaths(session.expandedProjectPaths);
 }
 
+void MainWindow::projectProperties()
+{
+    if (ProjectPropertiesDialog(mProjectDock->project(), this).exec() == QDialog::Accepted)
+        ScriptManager::instance().refreshExtensionsPaths();
+}
+
 void MainWindow::cut()
 {
     if (auto editor = mDocumentManager->currentEditor())
@@ -1965,14 +1986,12 @@ void MainWindow::updateWindowTitle()
 
 void MainWindow::showDonationDialog()
 {
-    DonationDialog donationDialog(this);
-    donationDialog.exec();
+    DonationDialog(this).exec();
 }
 
 void MainWindow::aboutTiled()
 {
-    AboutDialog aboutDialog(this);
-    aboutDialog.exec();
+    AboutDialog(this).exec();
 }
 
 void MainWindow::retranslateUi()
diff --git a/src/tiled/mainwindow.h b/src/tiled/mainwindow.h
index 09993d21c0..a17732e60c 100644
--- a/src/tiled/mainwindow.h
+++ b/src/tiled/mainwindow.h
@@ -91,6 +91,8 @@ class MainWindow : public QMainWindow
      */
     bool openFile(const QString &fileName, FileFormat *fileFormat = nullptr);
 
+    Project &project() const;
+
     static MainWindow *instance();
 
 protected:
@@ -125,6 +127,7 @@ class MainWindow : public QMainWindow
     void closeProject();
     void switchProject(Project project);
     void restoreSession();
+    void projectProperties();
 
     void cut();
     void copy();
diff --git a/src/tiled/mainwindow.ui b/src/tiled/mainwindow.ui
index e062b188b6..c272777382 100644
--- a/src/tiled/mainwindow.ui
+++ b/src/tiled/mainwindow.ui
@@ -129,7 +129,7 @@
     </widget>
     <addaction name="actionAddExternalTileset"/>
     <addaction name="separator"/>
-    <addaction name="actionNewWorld" />
+    <addaction name="actionNewWorld"/>
     <addaction name="actionLoadWorld"/>
     <addaction name="menuUnloadWorld"/>
     <addaction name="menuSaveWorld"/>
@@ -214,6 +214,8 @@
     <addaction name="separator"/>
     <addaction name="actionAddFolderToProject"/>
     <addaction name="actionRefreshProjectFolders"/>
+    <addaction name="separator"/>
+    <addaction name="actionProjectProperties"/>
    </widget>
    <addaction name="menuFile"/>
    <addaction name="menuEdit"/>
@@ -760,6 +762,15 @@
     <string>Ctrl+Shift+M</string>
    </property>
   </action>
+  <action name="actionProjectProperties">
+   <property name="icon">
+    <iconset resource="tiled.qrc">
+     <normaloff>:/images/16/document-properties.png</normaloff>:/images/16/document-properties.png</iconset>
+   </property>
+   <property name="text">
+    <string>Project &amp;Properties...</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <resources>
diff --git a/src/tiled/newsbutton.cpp b/src/tiled/newsbutton.cpp
index 56f49a7aac..72a2a1fe32 100644
--- a/src/tiled/newsbutton.cpp
+++ b/src/tiled/newsbutton.cpp
@@ -106,7 +106,10 @@ void NewsButton::showNewsMenu()
     auto &feed = NewsFeed::instance();
 
     for (const NewsItem &newsItem : feed.newsItems()) {
-        QAction *action = newsFeedMenu->addAction(newsItem.title);
+        QAction *action = newsFeedMenu->addAction(newsItem.title, [=] {
+            QDesktopServices::openUrl(newsItem.link);
+            NewsFeed::instance().markRead(newsItem);
+        });
 
         if (feed.isUnread(newsItem)) {
             QFont f = action->font();
@@ -116,11 +119,6 @@ void NewsButton::showNewsMenu()
         } else {
             action->setIcon(mReadIcon);
         }
-
-        connect(action, &QAction::triggered, [=] {
-            QDesktopServices::openUrl(newsItem.link);
-            NewsFeed::instance().markRead(newsItem);
-        });
     }
 
     newsFeedMenu->addSeparator();
diff --git a/src/tiled/project.cpp b/src/tiled/project.cpp
index 22af3b7887..6e899e7769 100644
--- a/src/tiled/project.cpp
+++ b/src/tiled/project.cpp
@@ -41,6 +41,12 @@ Project::Project()
 
 bool Project::save(const QString &fileName)
 {
+    QString extensionsPath = mExtensionsPath;
+
+    // Initialize extensions path to its default value
+    if (mFileName.isEmpty() && extensionsPath.isEmpty())
+        extensionsPath = QFileInfo(fileName).dir().filePath(QLatin1String("extensions"));
+
     QJsonObject project;
 
     const QDir dir = QFileInfo(fileName).dir();
@@ -51,6 +57,7 @@ bool Project::save(const QString &fileName)
         folders.append(relative(dir, folder));
 
     project.insert(QLatin1String("folders"), folders);
+    project.insert(QLatin1String("extensionsPath"), relative(dir, extensionsPath));
 
     QJsonDocument document(project);
 
@@ -63,6 +70,7 @@ bool Project::save(const QString &fileName)
         return false;
 
     mFileName = fileName;
+    mExtensionsPath = extensionsPath;
     return true;
 }
 
@@ -85,6 +93,8 @@ bool Project::load(const QString &fileName)
 
     QJsonObject project = document.object();
 
+    mExtensionsPath = QDir::cleanPath(dir.absoluteFilePath(project.value(QLatin1String("extensionsFolder")).toString(QLatin1String("extensions"))));
+
     const QJsonArray folders = project.value(QLatin1String("folders")).toArray();
     for (const QJsonValue &folderValue : folders)
         mFolders.append(QDir::cleanPath(dir.absoluteFilePath(folderValue.toString())));
diff --git a/src/tiled/project.h b/src/tiled/project.h
index 9cf08433ef..4e5e727ab4 100644
--- a/src/tiled/project.h
+++ b/src/tiled/project.h
@@ -35,10 +35,10 @@ class Project
 
     void addFolder(const QString &folder);
     void removeFolder(int index);
-    void refreshFolders();
-
     const QStringList &folders() const;
 
+    QString mExtensionsPath;
+
 private:
     QString mFileName;
     QStringList mFolders;
diff --git a/src/tiled/projectpropertiesdialog.cpp b/src/tiled/projectpropertiesdialog.cpp
new file mode 100644
index 0000000000..c28183c4c7
--- /dev/null
+++ b/src/tiled/projectpropertiesdialog.cpp
@@ -0,0 +1,69 @@
+/*
+ * projectpropertiesdialog.cpp
+ * Copyright 2020, Thorbjørn Lindeijer <bjorn@lindeijer.nl>
+ *
+ * This file is part of Tiled.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "projectpropertiesdialog.h"
+#include "ui_projectpropertiesdialog.h"
+
+#include "project.h"
+#include "utils.h"
+#include "varianteditorfactory.h"
+#include "variantpropertymanager.h"
+
+#include <QtGroupPropertyManager>
+
+namespace Tiled {
+
+ProjectPropertiesDialog::ProjectPropertiesDialog(Project &project, QWidget *parent)
+    : QDialog(parent)
+    , ui(new Ui::ProjectPropertiesDialog)
+    , mProject(project)
+{
+    ui->setupUi(this);
+
+    auto variantPropertyManager = new VariantPropertyManager(this);
+    auto variantEditorFactory = new VariantEditorFactory(this);
+    auto groupPropertyManager = new QtGroupPropertyManager(this);
+
+    ui->propertyBrowser->setFactoryForManager<QtVariantPropertyManager>(variantPropertyManager,
+                                                                        variantEditorFactory);
+
+    auto groupProperty = groupPropertyManager->addProperty(tr("Extensions"));
+    mExtensionPathProperty = variantPropertyManager->addProperty(filePathTypeId(), tr("Directory"));
+    mExtensionPathProperty->setValue(project.mExtensionsPath);
+    mExtensionPathProperty->setAttribute(QStringLiteral("directory"), true);
+
+    groupProperty->addSubProperty(mExtensionPathProperty);
+
+    ui->propertyBrowser->addProperty(groupProperty);
+}
+
+ProjectPropertiesDialog::~ProjectPropertiesDialog()
+{
+    delete ui;
+}
+
+void ProjectPropertiesDialog::accept()
+{
+    mProject.mExtensionsPath = mExtensionPathProperty->value().toString();
+
+    QDialog::accept();
+}
+
+} // namespace Tiled
diff --git a/src/tiled/projectpropertiesdialog.h b/src/tiled/projectpropertiesdialog.h
new file mode 100644
index 0000000000..756997853d
--- /dev/null
+++ b/src/tiled/projectpropertiesdialog.h
@@ -0,0 +1,52 @@
+/*
+ * projectpropertiesdialog.h
+ * Copyright 2020, Thorbjørn Lindeijer <bjorn@lindeijer.nl>
+ *
+ * This file is part of Tiled.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QDialog>
+
+class QtVariantProperty;
+
+namespace Ui {
+class ProjectPropertiesDialog;
+}
+
+namespace Tiled {
+
+class Project;
+
+class ProjectPropertiesDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit ProjectPropertiesDialog(Project &project, QWidget *parent = nullptr);
+    ~ProjectPropertiesDialog() override;
+
+    void accept() override;
+
+private:
+    Ui::ProjectPropertiesDialog *ui;
+
+    Project &mProject;
+    QtVariantProperty *mExtensionPathProperty;
+};
+
+} // namespace Tiled
diff --git a/src/tiled/projectpropertiesdialog.ui b/src/tiled/projectpropertiesdialog.ui
new file mode 100644
index 0000000000..5194942dc4
--- /dev/null
+++ b/src/tiled/projectpropertiesdialog.ui
@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>ProjectPropertiesDialog</class>
+ <widget class="QDialog" name="ProjectPropertiesDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>575</width>
+    <height>168</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Project Properties</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QtGroupBoxPropertyBrowser" name="propertyBrowser" native="true"/>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QtGroupBoxPropertyBrowser</class>
+   <extends>QWidget</extends>
+   <header location="global">QtGroupBoxPropertyBrowser</header>
+   <container>1</container>
+  </customwidget>
+ </customwidgets>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>ProjectPropertiesDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>ProjectPropertiesDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>
diff --git a/src/tiled/scriptmanager.cpp b/src/tiled/scriptmanager.cpp
index b826d325ed..840fd05819 100644
--- a/src/tiled/scriptmanager.cpp
+++ b/src/tiled/scriptmanager.cpp
@@ -30,8 +30,11 @@
 #include "editabletilelayer.h"
 #include "editabletileset.h"
 #include "logginginterface.h"
+#include "mainwindow.h"
 #include "mapeditor.h"
 #include "mapview.h"
+#include "preferences.h"
+#include "project.h"
 #include "regionvaluetype.h"
 #include "scriptedaction.h"
 #include "scriptedfileformat.h"
@@ -71,7 +74,7 @@ void ScriptManager::deleteInstance()
 }
 
 /*
- * mJSEngine needs to be QQmlEngine for the "Qt" module to be available, which
+ * mEngine needs to be QQmlEngine for the "Qt" module to be available, which
  * is necessary to pass things like QSize or QPoint to some API functions
  * (using Qt.size and Qt.point).
  *
@@ -81,9 +84,6 @@ void ScriptManager::deleteInstance()
 
 ScriptManager::ScriptManager(QObject *parent)
     : QObject(parent)
-    , mEngine(new QQmlEngine(this))
-    , mModule(new ScriptModule(this))
-    , mTempCount(0)
 {
     qRegisterMetaType<Cell>();
     qRegisterMetaType<EditableAsset*>();
@@ -114,34 +114,21 @@ ScriptManager::ScriptManager(QObject *parent)
     connect(&mWatcher, &FileSystemWatcher::pathsChanged,
             this, &ScriptManager::scriptFilesChanged);
 
-    const QString configLocation { QStandardPaths::writableLocation(QStandardPaths::AppConfigLocation) };
+    const QString configLocation { Preferences::configLocation() };
     if (!configLocation.isEmpty()) {
         mExtensionsPath = QDir{configLocation}.filePath(QStringLiteral("extensions"));
 
         if (!QFile::exists(mExtensionsPath))
             QDir().mkpath(mExtensionsPath);
-
-        mExtensionsPaths.append(mExtensionsPath);
     }
 }
 
 void ScriptManager::initialize()
 {
-    QJSValue globalObject = mEngine->globalObject();
-    globalObject.setProperty(QStringLiteral("tiled"), mEngine->newQObject(mModule));
-#if QT_VERSION >= 0x050800
-    globalObject.setProperty(QStringLiteral("TextFile"), mEngine->newQMetaObject<ScriptTextFile>());
-    globalObject.setProperty(QStringLiteral("BinaryFile"), mEngine->newQMetaObject<ScriptBinaryFile>());
-    globalObject.setProperty(QStringLiteral("Layer"), mEngine->newQMetaObject<EditableLayer>());
-    globalObject.setProperty(QStringLiteral("MapObject"), mEngine->newQMetaObject<EditableMapObject>());
-    globalObject.setProperty(QStringLiteral("ObjectGroup"), mEngine->newQMetaObject<EditableObjectGroup>());
-    globalObject.setProperty(QStringLiteral("Terrain"), mEngine->newQMetaObject<EditableTerrain>());
-    globalObject.setProperty(QStringLiteral("Tile"), mEngine->newQMetaObject<EditableTile>());
-    globalObject.setProperty(QStringLiteral("TileLayer"), mEngine->newQMetaObject<EditableTileLayer>());
-    globalObject.setProperty(QStringLiteral("TileMap"), mEngine->newQMetaObject<EditableMap>());
-    globalObject.setProperty(QStringLiteral("Tileset"), mEngine->newQMetaObject<EditableTileset>());
-#endif
+    Q_ASSERT(!mEngine && !mModule);
 
+    refreshExtensionsPaths();
+    setupEngine();
     loadExtensions();
 }
 
@@ -275,15 +262,37 @@ void ScriptManager::reset()
     Tiled::INFO(tr("Resetting script engine"));
 
     mWatcher.clear();
+
     delete mEngine;
     delete mModule;
 
+    mEngine = nullptr;
+    mModule = nullptr;
     mTempCount = 0;
 
+    setupEngine();
+    loadExtensions();
+}
+
+void ScriptManager::setupEngine()
+{
     mEngine = new QQmlEngine(this);
     mModule = new ScriptModule(this);
 
-    initialize();
+    QJSValue globalObject = mEngine->globalObject();
+    globalObject.setProperty(QStringLiteral("tiled"), mEngine->newQObject(mModule));
+#if QT_VERSION >= 0x050800
+    globalObject.setProperty(QStringLiteral("TextFile"), mEngine->newQMetaObject<ScriptTextFile>());
+    globalObject.setProperty(QStringLiteral("BinaryFile"), mEngine->newQMetaObject<ScriptBinaryFile>());
+    globalObject.setProperty(QStringLiteral("Layer"), mEngine->newQMetaObject<EditableLayer>());
+    globalObject.setProperty(QStringLiteral("MapObject"), mEngine->newQMetaObject<EditableMapObject>());
+    globalObject.setProperty(QStringLiteral("ObjectGroup"), mEngine->newQMetaObject<EditableObjectGroup>());
+    globalObject.setProperty(QStringLiteral("Terrain"), mEngine->newQMetaObject<EditableTerrain>());
+    globalObject.setProperty(QStringLiteral("Tile"), mEngine->newQMetaObject<EditableTile>());
+    globalObject.setProperty(QStringLiteral("TileLayer"), mEngine->newQMetaObject<EditableTileLayer>());
+    globalObject.setProperty(QStringLiteral("TileMap"), mEngine->newQMetaObject<EditableMap>());
+    globalObject.setProperty(QStringLiteral("Tileset"), mEngine->newQMetaObject<EditableTileset>());
+#endif
 }
 
 void ScriptManager::scriptFilesChanged(const QStringList &scriptFiles)
@@ -292,4 +301,33 @@ void ScriptManager::scriptFilesChanged(const QStringList &scriptFiles)
     reset();
 }
 
+void ScriptManager::refreshExtensionsPaths()
+{
+    QStringList extensionsPaths;
+
+    if (!mExtensionsPath.isEmpty())
+        extensionsPaths.append(mExtensionsPath);
+
+    // Add extensions path from project
+    auto &projectExtensionsPath = MainWindow::instance()->project().mExtensionsPath;
+    if (!projectExtensionsPath.isEmpty()) {
+        const QFileInfo info(projectExtensionsPath);
+        if (info.exists() && info.isDir())
+            extensionsPaths.append(projectExtensionsPath);
+    }
+
+    extensionsPaths.sort();
+    extensionsPaths.removeDuplicates();
+
+    if (extensionsPaths == mExtensionsPaths)
+        return;
+
+    mExtensionsPaths.swap(extensionsPaths);
+
+    if (mEngine) {
+        Tiled::INFO(tr("Extensions paths changed: %1").arg(mExtensionsPaths.join(QLatin1String(", "))));
+        reset();
+    }
+}
+
 } // namespace Tiled
diff --git a/src/tiled/scriptmanager.h b/src/tiled/scriptmanager.h
index 63d8ed9cf6..fa81ee3a0d 100644
--- a/src/tiled/scriptmanager.h
+++ b/src/tiled/scriptmanager.h
@@ -62,23 +62,25 @@ class ScriptManager : public QObject
     void throwError(const QString &message);
     void throwNullArgError(int argNumber);
 
-    void reset();
+    void refreshExtensionsPaths();
 
 private:
     explicit ScriptManager(QObject *parent = nullptr);
     ~ScriptManager() = default;
 
+    void reset();
+    void setupEngine();
     void scriptFilesChanged(const QStringList &scriptFiles);
 
     void loadExtensions();
     void loadExtension(const QString &path);
 
-    QJSEngine *mEngine;
-    ScriptModule *mModule;
+    QJSEngine *mEngine = nullptr;
+    ScriptModule *mModule = nullptr;
     FileSystemWatcher mWatcher;
     QString mExtensionsPath;
     QStringList mExtensionsPaths;
-    int mTempCount;
+    int mTempCount = 0;
 
     static ScriptManager *mInstance;
 };
diff --git a/src/tiled/tiled.pro b/src/tiled/tiled.pro
index 53e79930d6..e743cae28a 100644
--- a/src/tiled/tiled.pro
+++ b/src/tiled/tiled.pro
@@ -190,6 +190,7 @@ SOURCES += aboutdialog.cpp \
     project.cpp \
     projectdock.cpp \
     projectmodel.cpp \
+    projectpropertiesdialog.cpp \
     preferencesdialog.cpp \
     propertiesdock.cpp \
     propertybrowser.cpp \
@@ -427,6 +428,7 @@ HEADERS += aboutdialog.h \
     project.h \
     projectdock.h \
     projectmodel.h \
+    projectpropertiesdialog.h \
     propertiesdock.h \
     propertybrowser.h \
     raiselowerhelper.h \
@@ -529,6 +531,7 @@ FORMS += aboutdialog.ui \
     objecttypeseditor.ui \
     offsetmapdialog.ui \
     preferencesdialog.ui \
+    projectpropertiesdialog.ui \
     resizedialog.ui \
     shortcutsettingspage.ui \
     texteditordialog.ui \
diff --git a/src/tiled/tiled.qbs b/src/tiled/tiled.qbs
index e6cde3c584..615372b01f 100644
--- a/src/tiled/tiled.qbs
+++ b/src/tiled/tiled.qbs
@@ -380,6 +380,9 @@ QtGuiApplication {
         "projectdock.h",
         "projectmodel.cpp",
         "projectmodel.h",
+        "projectpropertiesdialog.cpp",
+        "projectpropertiesdialog.h",
+        "projectpropertiesdialog.ui",
         "propertiesdock.cpp",
         "propertiesdock.h",
         "propertybrowser.cpp",
diff --git a/src/tiled/utils.cpp b/src/tiled/utils.cpp
index 94a1b97d5e..9f5c8d0337 100644
--- a/src/tiled/utils.cpp
+++ b/src/tiled/utils.cpp
@@ -291,14 +291,12 @@ void addFileManagerActions(QMenu &menu, const QString &fileName)
     if (fileName.isEmpty())
         return;
 
-    QAction *copyPath = menu.addAction(QCoreApplication::translate("Utils", "Copy File Path"));
-    QObject::connect(copyPath, &QAction::triggered, [fileName] {
+    menu.addAction(QCoreApplication::translate("Utils", "Copy File Path"), [fileName] {
         QClipboard *clipboard = QApplication::clipboard();
         clipboard->setText(QDir::toNativeSeparators(fileName));
     });
 
-    QAction *openFolder = menu.addAction(QCoreApplication::translate("Utils", "Open Containing Folder..."));
-    QObject::connect(openFolder, &QAction::triggered, [fileName] {
+    menu.addAction(QCoreApplication::translate("Utils", "Open Containing Folder..."), [fileName] {
         showInFileManager(fileName);
     });
 }
diff --git a/src/tiled/varianteditorfactory.cpp b/src/tiled/varianteditorfactory.cpp
index 38f103f834..fb8d0d5df8 100644
--- a/src/tiled/varianteditorfactory.cpp
+++ b/src/tiled/varianteditorfactory.cpp
@@ -111,6 +111,7 @@ QWidget *VariantEditorFactory::createEditor(QtVariantPropertyManager *manager,
         FilePath filePath = manager->value(property).value<FilePath>();
         editor->setFileUrl(filePath.url);
         editor->setFilter(manager->attributeValue(property, QLatin1String("filter")).toString());
+        editor->setIsDirectory(manager->attributeValue(property, QLatin1String("directory")).toBool());
         mCreatedFileEdits[property].append(editor);
         mFileEditToProperty[editor] = property;
 
@@ -245,6 +246,9 @@ void VariantEditorFactory::slotPropertyAttributeChanged(QtProperty *property,
         if (attribute == QLatin1String("filter")) {
             for (FileEdit *edit : qAsConst(mCreatedFileEdits)[property])
                 edit->setFilter(value.toString());
+        } else if (attribute == QLatin1String("directory")) {
+            for (FileEdit *edit : qAsConst(mCreatedFileEdits)[property])
+                edit->setIsDirectory(value.toBool());
         }
     }
     else if (mCreatedComboBoxes.contains(property)) {
diff --git a/src/tiled/variantpropertymanager.cpp b/src/tiled/variantpropertymanager.cpp
index 4c5f0c4f02..8761ad3fca 100644
--- a/src/tiled/variantpropertymanager.cpp
+++ b/src/tiled/variantpropertymanager.cpp
@@ -53,6 +53,8 @@ MapObject *DisplayObjectRef::object() const
 
 VariantPropertyManager::VariantPropertyManager(QObject *parent)
     : QtVariantPropertyManager(parent)
+    , mFilterAttribute(QStringLiteral("filter"))
+    , mDirectoryAttribute(QStringLiteral("directory"))
     , mSuggestionsAttribute(QStringLiteral("suggestions"))
     , mMultilineAttribute(QStringLiteral("multiline"))
     , mImageMissingIcon(QStringLiteral("://images/16/image-missing.png"))
@@ -68,7 +70,7 @@ VariantPropertyManager::VariantPropertyManager(QObject *parent)
 QVariant VariantPropertyManager::value(const QtProperty *property) const
 {
     if (mValues.contains(property))
-        return mValues[property].value;
+        return mValues[property];
     if (m_alignValues.contains(property))
         return QVariant::fromValue(m_alignValues.value(property));
     return QtVariantPropertyManager::value(property);
@@ -100,8 +102,9 @@ int VariantPropertyManager::valueType(int propertyType) const
 QStringList VariantPropertyManager::attributes(int propertyType) const
 {
     if (propertyType == filePathTypeId()) {
-        return QStringList {
-            QStringLiteral("filter")
+        return {
+            mFilterAttribute,
+            mDirectoryAttribute
         };
     }
     return QtVariantPropertyManager::attributes(propertyType);
@@ -111,8 +114,10 @@ int VariantPropertyManager::attributeType(int propertyType,
                                           const QString &attribute) const
 {
     if (propertyType == filePathTypeId()) {
-        if (attribute == QLatin1String("filter"))
+        if (attribute == mFilterAttribute)
             return QVariant::String;
+        if (attribute == mDirectoryAttribute)
+            return QVariant::Bool;
         return 0;
     }
     return QtVariantPropertyManager::attributeType(propertyType, attribute);
@@ -121,9 +126,11 @@ int VariantPropertyManager::attributeType(int propertyType,
 QVariant VariantPropertyManager::attributeValue(const QtProperty *property,
                                                 const QString &attribute) const
 {
-    if (mValues.contains(property)) {
-        if (attribute == QLatin1String("filter"))
-            return mValues[property].filter;
+    if (mFilePathAttributes.contains(property)) {
+        if (attribute == mFilterAttribute)
+            return mFilePathAttributes[property].filter;
+        if (attribute == mDirectoryAttribute)
+            return mFilePathAttributes[property].directory;
         return QVariant();
     }
     if (mStringAttributes.contains(property)) {
@@ -169,7 +176,7 @@ QString VariantPropertyManager::objectRefLabel(const MapObject *object) const
 QString VariantPropertyManager::valueText(const QtProperty *property) const
 {
     if (mValues.contains(property)) {
-        QVariant value = mValues[property].value;
+        QVariant value = mValues[property];
         int typeId = propertyType(property);
 
         if (typeId == displayObjectRefTypeId()) {
@@ -222,7 +229,7 @@ QString VariantPropertyManager::valueText(const QtProperty *property) const
 QIcon VariantPropertyManager::valueIcon(const QtProperty *property) const
 {
     if (mValues.contains(property)) {
-        QVariant value = mValues[property].value;
+        QVariant value = mValues[property];
         QString filePath;
         int typeId = propertyType(property);
 
@@ -257,11 +264,10 @@ QIcon VariantPropertyManager::valueIcon(const QtProperty *property) const
 void VariantPropertyManager::setValue(QtProperty *property, const QVariant &value)
 {
     if (mValues.contains(property)) {
-        Data d = mValues[property];
-        if (d.value == value)
+        QVariant &storedValue = mValues[property];
+        if (storedValue == value)
             return;
-        d.value = value;
-        mValues[property] = d;
+        storedValue = value;
         emit propertyChanged(property);
         emit valueChanged(property, value);
         return;
@@ -297,17 +303,22 @@ void VariantPropertyManager::setAttribute(QtProperty *property,
                                           const QString &attribute,
                                           const QVariant &val)
 {
-    if (mValues.contains(property)) {
-        if (attribute == QLatin1String("filter")) {
+    if (mFilePathAttributes.contains(property)) {
+        FilePathAttributes &attributes = mFilePathAttributes[property];
+        if (attribute == mFilterAttribute) {
             if (val.type() != QVariant::String && !val.canConvert(QVariant::String))
                 return;
-            QString str = val.toString();
-            Data d = mValues[property];
-            if (d.filter == str)
+            QString filter = val.toString();
+            if (attributes.filter == filter)
+                return;
+            attributes.filter = filter;
+            emit attributeChanged(property, attribute, filter);
+        } else if (attribute == mDirectoryAttribute) {
+            bool directory = val.toBool();
+            if (attributes.directory == directory)
                 return;
-            d.filter = str;
-            mValues[property] = d;
-            emit attributeChanged(property, attribute, str);
+            attributes.directory = directory;
+            emit attributeChanged(property, attribute, directory);
         }
         return;
     }
@@ -332,7 +343,9 @@ void VariantPropertyManager::initializeProperty(QtProperty *property)
     if (type == filePathTypeId()
             || type == displayObjectRefTypeId()
             || type == tilesetParametersTypeId()) {
-        mValues[property] = Data();
+        mValues[property] = QVariant();
+        if (type == filePathTypeId())
+            mFilePathAttributes[property] = FilePathAttributes();
     } else if (type == QVariant::String) {
         mStringAttributes[property] = StringAttributes();
     } else if (type == alignmentTypeId()) {
@@ -365,6 +378,7 @@ void VariantPropertyManager::initializeProperty(QtProperty *property)
 void VariantPropertyManager::uninitializeProperty(QtProperty *property)
 {
     mValues.remove(property);
+    mFilePathAttributes.remove(property);
     mStringAttributes.remove(property);
     m_alignValues.remove(property);
 
diff --git a/src/tiled/variantpropertymanager.h b/src/tiled/variantpropertymanager.h
index 9e6fc8c733..2c800e143f 100644
--- a/src/tiled/variantpropertymanager.h
+++ b/src/tiled/variantpropertymanager.h
@@ -91,11 +91,13 @@ public slots:
     void slotPropertyDestroyed(QtProperty *property);
     QString objectRefLabel(const MapObject *object) const;
 
-    struct Data {
-        QVariant value;
+    QMap<const QtProperty *, QVariant> mValues;
+
+    struct FilePathAttributes {
         QString filter;
+        bool directory = false;
     };
-    QMap<const QtProperty *, Data> mValues;
+    QMap<const QtProperty *, FilePathAttributes> mFilePathAttributes;
 
     struct StringAttributes {
         QStringList suggestions;
@@ -116,6 +118,8 @@ public slots:
     PropertyToPropertyMap m_alignHToProperty;
     PropertyToPropertyMap m_alignVToProperty;
 
+    const QString mFilterAttribute;
+    const QString mDirectoryAttribute;
     const QString mSuggestionsAttribute;
     const QString mMultilineAttribute;
     QIcon mImageMissingIcon;