Disabling compositing leads to black line around some menus

Submitted by Adam Purkrt

Assigned to Nick Schermer

Link to original bug (#14160)

Description

Version: 4.12.0

Adam Purkrt said:

Disabling compositing leads to black line around some menus (see the screenshots)

1. start with default xfce4 config (compositing on)
2. disable compositing - unselect Settings/Window Manager Tweaks/Enable display compositing
3. there is an ugly ~10px wide black stripe around Applications menu and panel right mouse button menu

Strangely, the line (stripe) is only around top level applications menu, not around submenus. The submenus lacks the proper 1px thick border, though. For panel rmb menu, the thick black line is both around context menu and its submenu.

Upon restarting XFCE, the black line goes away.

Adam Purkrt uploaded an attachment:

Applications menu with black line around it immediately after disabling compositing

Attachment 7531, "Applications menu with black line":

Adam Purkrt uploaded an attachment:

Panel menu with black line around it immediately after disabling compositing.

Attachment 7532, "Panel menu with black line around it.":

Adam Purkrt uploaded an attachment:

Correct applications menu after restart (compositing off). Correct 1px gray wide border of the menu.

Attachment 7533, "Correct applications menu after restart":

Adam Purkrt said:

Sorry for the empty description and adding description as a comment, I inadvertently hit enter.

Adam Purkrt said:

xfwm4 4.13.0git.17753656

mirh @mirh said:

Could this have been bug 14577?

Adam Purkrt said:

I would not say so. The bug is still there. I just retested and it triggers after the following set of steps

1. Turn on display compositing (Settings/Window Manager Tweaks/Compositor/check Enable display compositing)
2. Log out of Xfce - I use startx to start the X server, so logging out shut downs the X server
3. Start Xfce again - startx in my case (which starts startxfce4 --with-ck-launch)
4. Turn off display compositing (uncheck Enable display compositing)
5. Click on "Applications" menu - the menu will appear with a thick black line around it.

Upon another restart of X, the black line around the menu goes away. So this is admittedly a rather minor bug (you encounter it only during the X session which started with enabled display compositing and during which the compositing was switched off).

Adam Purkrt commented on attachment 7532:

Marking this attachment as obsolete, since the panel menus are now always ok. I am unable to trigger the bug for them. But the Applications menu still can have the thick black line around, under the conditions described above.

added 5. Compositor label

From Olivier's xfce4-panel#406 (comment 23108)

It shows as black above because you turned the compositor off after the client was started. First and foremost, please don't do that, clients such as gtk applications cannot deal with the compositor being turned off and will shows a black area instead of the transparency expected.

That said, the black area you show above in your screenshot is part of the client, some of it is used for resize handles, the rest is shadows.

The shadows are excluded from the input mask, meaning that events will get though, but obviously the resize part needs to reach the client window and will prevent the event from reaching what's underneath.

closed