ltsgraph file selection not working on Linux about mcrl2

[mlaveaux]

I have taken an in depth look at this issue and also other GUI related issues and the conclusion is that the state of Qt support together with Wayland is just extremely poor. Unfortunately, these are all upstream issues and unfortunately we cannot do much about it. First of all, under X11 these issues do not appear.

Running Ubuntu 22.04 with default configuration the screen shot below shows that the open file dialog window does exist, but it is not rendered properly.

Running ltsgraph from the terminal shows the following warning: "Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.". A mediocre workaround is to install the qt5-wayland package (which was not installed by default) and run ltsgraph as follows: QT_QPA_PLATFORM=wayland ltsgraph. Then the open file dialog will appear when you click away from ltsgraph.

Another weird workaround is to use 'XDG_CURRENT_DESKTOP=kde ltsgraph' even if you don't use Plasma, it will use the Qt file dialog instead of a native one and this seems to work.

[mhvis]

I can confirm that the workaround to use XDG_CURRENT_DESKTOP=kde ltsgraph works for me. Thanks!

The environment is set for me by default as XDG_SESSION_TYPE=x11 and XDG_CURRENT_DESKTOP=pop:GNOME (I'm using X11).

[mlaveaux]

It's a bit surprising (and unfortunate) that these issues also occur under X11, because that did not seem to be the case when I tried it. However, since this workaround solves this particular issue we should be sure to note that down somewhere and besides that this issue can be considered resolved. Perhaps a move to Qt6 in due time will help resolve this.