gnome-shell freezes when pointer leaves VM screen and tiling window
When a window is dragged to the edge of the screen, it attaches / tiles to that half of the screen. If this happens while running GNOME in a virtual machine it is likely the pointer leaves the VM screen. This causes gnome-shell to freeze. Behaviour is very similar to Bug 762193, but can be triggered reliably.
System:
- Ubuntu 18.04
- GNOME 3.26.2
- Linux 4.13.0-32-generic #35 (closed)-Ubuntu SMP x86_64 GNU/Linux
- running in VirtualBox 5.2.6 r120293 on a Windows Host
MWE:
- Install a distro with GNOME in a virtual machine
- Open any application (e.g. gedit or gnome-terminal)
- Drag the application window to the right edge
- A semitransparent area will suggest the right half for the window
- If you drop the window w/o leaving the VM screen with the mouse pointer, everything works fine.
- If you drop the window in that you're leaving the VM screen, title bars won't respond and window focus change does not work anymore. However ALT+TAB still changes windows.
Workaround: Change to a Terminal (that you hopefully opened before), type "killall gnome-shell" and then "gnome-shell". The desktop now works again as expected until the next time you try pt. 3.2).
Note: A similar thing happens when you try to change the window size of a previously attached window. But I cannot reproduce this problem reliably, yet.