Bug 193083

Summary:	Keyboard input stops working after switching windows
Product:	[Unmaintained] khotkeys	Reporter:	Johannes Goller <jogojapan>
Component:	general	Assignee:	Michael Jansen <kde>
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	geroxp, jogojapan, kwin-bugs-null, zahl
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Johannes Goller 2009-05-18 09:28:26 UTC

Version: (using KDE 4.2.2)
Compiler: gcc 4.3
OS: Linux
Installed from: Fedora RPMs

Problem: After switching windows using Alt+Tab (but not if the mouse is used to switch windows), it sometimes, not always, occurs that no keyboard input takes any effect in the window I switched to, except that I can use Alt+Tab again to switch to another window.
Most of the time the problem is solved by switching to another window and back to the target window, using the mouse. Sometimes this does not help either, and I am forced to entirely shut the window and re-open the application.

I have seen this problem occur with two applications (i.e. if these applications were the target window I attempted to switch to): Konsole and Eclipse. I have never seen it occur with Firefox, although I am switching to that application a lot too.

I have a suspicion that this problem is related to the Anthy Skim Japanese input method, which is activated on my computer most of the time (and the problem only occurred when it was activated). To reproduce the bug, it might be necessary to enable Anthy Skim for Japanese (not necessarily actually switching to Japanese input, though).

The frequency with which the problem occurs is also related to the type of window I am in _before_ I switch. If that is Konsole, the problem _never_ occurs. If it is the Firefox browser, the problem _always_ occurs. If it is Eclipse, the problem _sometimes_ occurs.

The bug can also be triggered by switching tabs within the Konsole application. If I open 3 or more tabs in Konsole, and circle a couple of times between them, using keyboard shortcuts, I usually end up not being able to type into the windows any more.

Comment 1 A. Spehr 2009-05-19 05:06:51 UTC

*** Bug 185890 has been marked as a duplicate of this bug. ***

Comment 2 A. Spehr 2009-05-19 05:12:05 UTC

Possibly related to bug #171685, try the workaround in comment #56 (even if it isn't related, this might help). 

Do you have mouse gestures on?

Comment 3 Johannes Goller 2009-05-19 11:35:24 UTC

Thank you for the quick reply and the pointer to bug #171685 (which I hadn't been aware of).

To answer your questions:
(i) I tried the workaround suggested in Comment #56, i.e. I added the necessary lines to etc/X11/xorg.conf and restarted KDE. However, pressing the Ctrl+Alt+Keypad-Multiply/Keypad-Divide did not have any effect, neither on the problem, nor any other effect. In particular, it did not have the effects described in comment #59.

(ii) I don't think I have Mouse Gestures activated, but I am not entirely sure how to verify this. There does not seem to be any option related to this in systemsettings -> Input Actions. (Konqueror Gestures are enabled though). Note that I am using KDE 4.2.2, are there any Mouse Gestures in that version at all?

As a further comment, I think my issue is related to # 185890 as well as all those of #171685 that are triggered by Alt+Tab (which seem to form a subgroup that is perhaps independent of the other issues reported there).

I believe it should be easy to reproduce my issue by doing the following:
1. Open a konsole
2. Open Firefox
3. Click on the wallpaper, so neither of the two windows is activated
4. Use Alt+Tab to navigate to the Firefox window
5. Press Alt+Tab to switch to the konsole window
6. No input will work in the konsole window, except Alt+Tab

This produces the bug 100% of the time for me. The only applications running in parallel that might be worth mentioning are Skype and the Skim Anthy input method for Japanese.

I also tried resizing or moving the window, but that does not help. The only thing that helps (most of the time) is to use the mouse to switch to another window and back.

Comment 4 Michael Jansen 2009-05-21 16:46:59 UTC

Which alt+tab effect are you using? Btw. I will close that bug as a duplicate of #171685 "keyboard stops working in kde".

Mike

Comment 5 Johannes Goller 2009-05-22 04:30:22 UTC

Sure, feel free to mark it as duplicate, I can continue contributing on the other bug ticket.

Regarding this:
> Which alt+tab effect are you using?

Well, which ones are there? I mean the standard Alt+Tab which switches from one window (not: desktop) into another. If you hold Alt, a list of window-icons appears and by repeatedly pressing Tab you can select one of them. If you do not hold, just press Alt+Tab once, it switches to the window most recently visited before switching to the currently active window.

The bug occurs no matter if I hold or just press once.

As said above, a similar bug (perhaps the same underlying problem) occurs if I use Shift+Left/Right to switch between the tabs of a Konsole session. I am unsure whether that is a standard keyboard shortcut or perhaps one that I have defined.

Comment 6 Michael Jansen 2009-05-23 23:56:20 UTC


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