(Linux) Drag & drop file input doesn't work

[asitadmin]

(Issue migrated from Gitlab: Internal link)
[Ubuntu 20.04 Adoptium JDK 11]
Drag & drop file input doesn't work.
Maybe related to the known Ubuntu Issue & connected Desktop changes in #77 (closed)
Wanted behavior: Load PDF file per drag & drop.
If not feasible for this release, remove the drag option from the corresponding text (see screenshot):

[stefan2904]

for me this works (Ubuntu, X.org, i3wm, PDF-Over 4.4.5)