Strange creation of multiple desktops on Linux

Development
1

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.

Paolo

2

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?

3

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.

Paolo

4

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.

5

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.

Paolo

6

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

7

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.

8

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.

9

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

10

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

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