Bug 401225

Summary:	Mouse wheel events lost in LibreOffice when switching desktops
Product:	[Plasma] kwin	Reporter:	Mahendra Tallur <mahen>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal
Priority:	NOR
Version First Reported In:	5.14.3
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Mahendra Tallur 2018-11-19 21:03:03 UTC

SUMMARY

When switching back and forth between 2 desktops, mouse wheel events are not passed to LibreOffice anymore (unless clicked again).

STEPS TO REPRODUCE
1. You need 2 virtual desktops
2. On the first one, open a couple of windows, for instance Dolphin and Firefox
3. On the 2nd one, open a several pages long LibreOffice Writer document
4. Go back to the 1st desktop. Select the Dolphin window, then the Firefox one
5. Go back to the 2nd desktop. Try to use the mouse wheel to scroll the page

OBSERVED RESULT

Mouse wheel events are not taken into account ALTHOUGH keyboard events are.

EXPECTED RESULT

Mouse wheel should scroll the page -- which works before switching desktop or after clicking inside of the window again.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE Neon
KDE Plasma Version: 5.14.3
KDE Frameworks Version: 5.52.0
Qt Version: 5.11.2

X11 / NVIDIA proprietary drivers 415.13
Libreoffice Fresh 6.1.3.2

REMARKS

This behavior doesn't occur with some other GTK / Qt apps. (not the ones I tried, at least)

Comment 1 Mahendra Tallur 2018-11-19 21:11:28 UTC

To be more accurate : when the bug occurs, the mouse wheel, instead of scrolling the page (as it did just before switching desktops back & forth), has an effect on the toolbar.

Comment 2 Martin Flöser 2018-11-20 05:24:31 UTC

Please report to libre office. KWin is not responsible for mouse event handling on X11.

Comment 3 Mahendra Tallur 2018-11-20 08:36:10 UTC

Thanks again, Martin, for the prompt reply.

I found a similar report in the Libo bugtracker : https://bugs.documentfoundation.org/show_bug.cgi?id=119976

However, it hasn't been confirmed yet because it seems devs cannot reproduce it under non-KWin setups. How can we help identify the culprit ?

Cheers :)

Comment 4 Martin Flöser 2018-11-21 05:23:27 UTC

We recently saw that libre office depends on _NET_WM_STATE_FOCUSED, which KWin does not provide. Maybe that's related.