Disable Alt key to toggle Nav Menu Layer

[vexe]

Version/Branch of Dear ImGui

Version: 1.79 WIP (17803)
Branch: docking

Back-end/Renderer/Compiler/OS

Back-ends: imgui_impl_win32.cpp + imgui_impl_dx11.cpp
Compiler: MSVC
Operating System: Win7 64-bit & Win10 64-bit

My Issue/Question:

Is there any way to disable the "Press and release ALT to toggle menu behavior"? As I use ALT for commands in my text editor

The code I found relevant to this is this snippet:

// Keyboard: Press and Release ALT to toggle menu layer
    // FIXME: We lack an explicit IO variable for "is the imgui window focused", so compare mouse validity to detect the common case of back-end clearing releases all keys on ALT-TAB
    if (IsNavInputTest(ImGuiNavInput_KeyMenu_, ImGuiInputReadMode_Pressed))
        g.NavWindowingToggleLayer = true;
    if ((g.ActiveId == 0 || g.ActiveIdAllowOverlap) && g.NavWindowingToggleLayer && IsNavInputTest(ImGuiNavInput_KeyMenu_, ImGuiInputReadMode_Released))
        if (IsMousePosValid(&g.IO.MousePos) == IsMousePosValid(&g.IO.MousePosPrev))
            apply_toggle_layer = true;

Setting that apply_toggle_layer to false fixes my issue but ideally I don't want to touch any of this code.

Thanks for any pointers!

[roever]

This problem is even more pronounced with the German (and probably other) keyboard layouts. On the German layout several input characters are mapped to AltGr+other key, e.g. "[" is input using AltGr+8. When I use any text input widgets be them one line text input or editors, each time someone enters one of these symbols the focus jumps, making it very clunky to enter text containing these symbols.

I think that the proper solution would be to only do the menu action, when no other key has been pressed between down and up of the alt or altgr key.

[stormsc1]

Is there still no way of disabling this without changing ImGui itself?...

[pixtur]

I ran into the same issue, because I need to ALT for a snap modifier key while dragging controls. (SHIFT and CTRL are already used for other purposes). For me it's not a show stopper, though.

[kettek]

Same issue over here, for use with additional cursor controls for a 3D map editor. Would be really nice to have this be optional.

[rokups]

As a temporary workaround, when your application handles ALT key you may set ImGui::GetCurrentContext()->NavWindowingToggleLayer = true; on that frame. This of course is a not supported solution and requires imgui_internal.h included, so expect it to break without prior notice.

[ocornut]

I have forgotten to post here when releasing 1.89 in November, as well as forgetting to tag this specific post in my myriad of commits related to input ownership system. But this should now be solved.

Many of the API are still in imgui_internal.h and therefore have no demo, but the demo_input_owner_and_routing branch has some demo for it, in particular this commit shows ways to hook ALT:
1e00a85

The variety of options and how they can be used are quite subtle and complex. Generally you need some form of conditional to not just steal the Alt mod key globally

But TL;DR; as per your statement above:

• If you want to disable Alt while your text editor is active, you can call SetKeyOwner(ImGuiMod_Alt, id); in your widget code.
• You may call SetItemKeyOwner(ImGuiMod_Alt) after submitting the widget which is roughly equivalent to if (IsItemHovered() || IsItemActive()) { SetKeyOwner(....); }.

If you want Alt to be conditionally disabled at the time of its press or hold you can also do that.

(Linking to #2637, #2620, #2891, #3370, #3724, #4828, #5108, #5242, #5641 for related features)