Seamless Mode Virtual Desktop Switch - Wallpaper Artifacts

[mongorian]

I have observed a minor issue with seamless mode for a while now. This has persisted across Windows XP, Vista, and 7 hosts with Fedora 17, 18, and OpenSUSE 12.2 guests. All applicable OS and VirtualBox updates are installed and this issue is consistent across at least two host machines (one desktop, one laptop).

The problem occurs consistently, and is replicated as such...
Ensure you have more than one KDE Virtual Desktop (workspace) setup in the "Pager" applet in the taskbar

Switch to seamless mode (in KDE) - Linux taskbar shows correctly on top of Windows background (wallpaper)

Open any Linux window on KDE Virtual Desktop 1

Switch to any other KDE Virtual Desktop

Observe results:
The area of the (Windows) desktop that the Linux window occupied on Virtual Desktop 1 is now like a hole in the host background (wallpaper) showing through to the Linux wallpaper (as well as any widgets on the Linux desktop)

I searched around quite a bit to see if there are any existing topics on this already, but didn't find anything. Has anyone else observed this behavior? Any ideas on how to correct it, or is this a bug in VirtualBox? (it seems to be consistent across Linux distributions)

I say this is a minor issue since it does not make the entire VirtualBox product unusable, but it does basically makes Seamless mode unusable (for me at least). It just makes the workspace too messy and odd to use, and makes the experience seem buggy. Let me know if a screenshot of the behavior is needed and I will upload one.

[Perryg]

Taken from Chapter 14.2 Known issues of the users manual.

"Neither scale mode nor seamless mode work correctly with guests using OpenGL 3D
features (such as with compiz-enabled window managers)."

[mongorian]

Thanks for the quick reply. Disabling desktop effects in KDE does seem to correct this issue.

Is this something that is scheduled to be fixed in upcoming releases or is this more likely going to be a permanent issue?

[Perryg]

I don't think you can totally disable KDE. Try taking the check mark out of 3D in the display section of the guest settings and see if that helps.

[mongorian]

Hi - I'm not sure exactly what you mean by "I don't think you can totally disable KDE" - I only disabled the "Desktop Effects" feature within KDE. This is similar to Gnome's Compiz functionality, I believe.

I shutdown the guest and tried unchecking the "Enable 3D Acceleration" in the guest configuration. I then started the guest back up and confirmed that there was *no change* to the behavior of this bug. I then temporarily disabled the KDE "Desktop Effects" through the KDE System Settings (shortcut: Alt+Shift+F12) and confirmed that the bug was fixed that way. In the System Settings --> Desktop Effects screen you can disable these effects at KDE startup (i.e. permanently) as well.