Strange creation of multiple desktops on Linux

Hi all,
I am running Slicer in Arch Linux (gnome and wayland).
When I load an image in slicer, a strange thing happens in gnome: multiple desktops are added to the system.
In gnome there is always a new, fresh and empty desktop available, that is automatically created and added when in the last one appears at least a single window.
In this case, it creates n empty desktops (they can be also 10-20), without a specific reason.
Those desktops are destroyed when slicer is closed.

For me it is not a huge problem, I’m writing just to point it out.


Could this be related to the Dropdown menus spawn on other monitor issue?
Maybe not because that problem is kind of the reverse: open the popup on the primary monitor if the Slicer window is on a secondary one. But still it’s quite similar and the number of new screens seem to suggest there may be a connection.

@PaoloZaffino does this happen more if you open dropdown menus such as the module history button? Do these desktops appear all at once, or gradually as you use Slicer?

No, I think it is not related to that issue.

I explain better my situation:

I open slicer: it’s all ok.
I drag an nrrd into slicer: the import window appears and I see the first “strange” desktop (any image loaded yet).
I click load: I see for a second another windows (the progress bar I think) and when the volume is vislible in slicer I have in total 4 “strange” desktops (in addition to the usual empty one).

If I drag and load a second nrrd file I have 8 desktops that should not be there.


I did a web search and it seems that Qt-5.15 has compatibility issues with Wayland. If the issues are too annoying and we cannot implement workarounds then we may consider going back to Qt-5.12 on Linux.

The issue may be that popup windows do not get deleted properly. Maybe we can explicitly delete them, or avoid deleting and recreating popups and just hide/show them.

For me it’s not a problem, it was just for pointing it out.

Any plan on the QT side to fix Wayland issues in the next releases?
This could be the easiest solution.


Yes, eventually these errors will be fixed, but it does not seem to be a priority for Qt.

Just a note that for the factory build machines the Linux platform is the only one on Qt 5.11.2 while macOS and Windows are both on Qt 5.15.0.

Sorry for a quick topic bifurcation.

When I use home built Slicer under KDE/Wayland in Arch, 2D views are just black after loading an .nrrd file, and Volume Rendering does not show anything with GPU rendering. Do these work for you ? There are no problems with KDE/X11.

More topic related, I don’t see any extra desktops/activities after loading an .nrrd file with KDE/Wayland.

@chir.set no other issue on my side, it works perfectly.
I see just a bunch of additional desktops.

a little update: right now I’m using the nightly version 2020-08-25 and the multi-desktop problem disappeared.