Bug 188499

Summary:	Keyboard locks up reproducibly under certain combinations of Alt-Tab + desktop switching
Product:	[Plasma] kwin	Reporter:	Mark Williamson <maw48>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	danielstefanmader+kde, kde, maw48, michael, zegenie
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	unspecified
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Mark Williamson 2009-03-30 19:19:55 UTC

Version:           unknown (using 4.2.1 (KDE 4.2.1), Kubuntu packages)
OS:                Linux (i686) release 2.6.27-11-generic

My situation to reproduce is:

Manifests with composite enabled or disabled.  Lots of programs running on Desktop 1, Alt+Tab list set to show only the apps on current desktop.  A few apps running on Desktop 3.

Starting on Desktop 3, I Ctrl+F1 switch to Desktop 1 and then quickly do an Alt+Tab and keep holding down the Alt for a second.  An application switch occurs as expected but after releasing Alt I still cannot get keyboard focus in any application.

Pressing keys that would correspond to shortcuts in the titlebar's right click / Alt-F3 menu causes those actions to occur, although that menu is not visible.  e.g. "n" will minimise the current window, "e" opens the configuration dialog, "d" opens the "To Desktop" dialog.

Opening the right-click titlebar menu using the mouse, or sometimes opening the "To Desktop" dialog (by pressing "d") seems to clear this condition and keyboard focus returns to normal.

I run into this a lot because of my particular keyboard usage habits, YMMV.  I can reproduce it very reliably on this system.

Comment 1 Martin Flöser 2009-03-30 19:22:56 UTC

*** Bug 186039 has been marked as a duplicate of this bug. ***

Comment 2 Mark Williamson 2009-03-30 20:03:18 UTC

Further experimentation suggests this problem is occurring if (and only if) I am switching *to* a desktop that has many open windows.

Sometimes when it occurs the Alt+Tab switcher flickers briefly onto the screen, then disappears before any contents appear; sometimes I don't see the switcher at all.

Comment 3 Michael Liddle 2009-03-31 14:35:01 UTC

I've been getting a problem similar to this on openSUSE 11.0 (KDE factory builds) for quite a long time now too (since at least 4.1, but perhaps earlier), but was never able to work out enough details to file a report. I was never able to reproduce at will (but generally come across it roughly once a day). I was resorting to logging out to fix!

At any rate it sounds _very_ similar to what is describe here, except that I seem to be able to reproduce by Alt-tabbing _very_ quickly after the new desktop draws (I switch desktops using Alt+Shit+<arrow>). I don't need to hold Alt down for any particular period, and I get the window-list "flicker" version described above. I don't seem to get any keyboard response at all however (i.e. not even those triggering actions in the window menu).

Finally it would seem that left-clicking the window icon does indeed fix the problem!

Comment 4 Martin Flöser 2009-05-01 12:27:54 UTC

*** Bug 168204 has been marked as a duplicate of this bug. ***

Comment 5 Michael Jansen 2009-05-21 16:48:30 UTC


*** This bug has been marked as a duplicate of bug 171685 ***