Bug 427440

Summary:	Unity Editor fails to recognise mouse scrolling events
Product:	[Plasma] kwin	Reporter:	David <kitt997>
Component:	input	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UNMAINTAINED
Severity:	normal	CC:	kde, nate
Priority:	NOR
Version First Reported In:	5.18.5
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description David 2020-10-08 11:03:42 UTC

Hi everyone, dealing with a mind destroying issue here. 
I'm using Unity Editor (Unity Technologies) and can't have my mouse inputs being recognized properly. Clicks do work, scrolling (hence touchpad gestures) do not, resulting into the inability of scrolling menus and zooming views. This is a total disaster.
Have to note the program actually works under GNOME or other GTK based DEs. But I'd rather write here than using GNOME.

STEPS TO REPRODUCE
1. Download Unity Hub
2. Install any version of the Unity Editor
3. Open any project

OBSERVED RESULT
Inside menus, lists do not scroll (with mouse wheel), forcing you to manually click on the scroll bar. But what's worse, can't zoom in nor out any view, neither by keyboard!.

EXPECTED RESULT
Unity should of course handle mouse inputs correctly. I use tons of GTK apps without an issue.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.73.0
Qt Version: 5.14.2

ADDITIONAL INFORMATION
I'm not quite sure about the component I've selected here for the bug report. Sorry for any inconvenience.
BTW, tried tweaking Compositor settings and even disabling it with no success. I'm currently looking for a way to nest a GTK DE inside Xephyr, and try to keep using KDE. This should make clear to you how desperate my situation is.

Comment 1 Nate Graham 2020-10-08 15:16:55 UTC

That's very odd. KWin actually doesn't handle scrolling at all on X11, only on Wayland. On Wayland, it's possible that something KDE-related is involved, but on X11, this issue would be somewhere in the input stack (Libinput/Synaptics/Evdev) or in the app itself having a weird interaction with the rest of the environment.

Comment 2 David Edmundson 2020-10-08 15:43:14 UTC

Does this issue happen when run under openbox/icewm?
(you can run openbox --replace in an existing plasma session)

What is the value selected in 
system settings -> window management -> window behaviour->window actions ->mouse wheel?

Comment 3 David 2020-10-08 16:22:52 UTC

(In reply to Nate Graham from comment #1)
> That's very odd. KWin actually doesn't handle scrolling at all on X11, only
> on Wayland. On Wayland, it's possible that something KDE-related is
> involved, but on X11, this issue would be somewhere in the input stack
> (Libinput/Synaptics/Evdev) or in the app itself having a weird interaction
> with the rest of the environment.

I'm confused as well. Of course switching to Wayland makes no difference.
Though I've noticed something interesting, maybe it sounds meaningful to you. If I log in to Plasma, log out then log in to GNOME, Unity no longer works. Put simply, Unity only works under GNOME unless I start Plasma: after that, stops working.

Comment 4 David 2020-10-08 16:25:45 UTC

(In reply to David Edmundson from comment #2)
> Does this issue happen when run under openbox/icewm?
> (you can run openbox --replace in an existing plasma session)
> 
> What is the value selected in 
> system settings -> window management -> window behaviour->window actions
> ->mouse wheel?

It's set to "scroll".
Neither mouse nor touchpad work.

Comment 5 David 2020-10-08 16:30:20 UTC

(In reply to David Edmundson from comment #2)
> Does this issue happen when run under openbox/icewm?
> (you can run openbox --replace in an existing plasma session)

Still happens. Unity works correctly instead, if I log in to Openbox directly.

Comment 6 Vlad Zahorodnii 2020-10-09 07:24:12 UTC

> Still happens.
Did you run openbox --replace before starting unity?

Comment 7 David 2020-10-09 08:38:02 UTC

(In reply to Vlad Zahorodnii from comment #6)
> > Still happens.
> Did you run openbox --replace before starting unity?

I've just tried, same result.

I'm adding another bit of the puzzle here. I've noticed two more things:
1) After a while using the application, it starts loosing responsiveness even to L/R clicks, in every area of the window except the main menu. Have to repeat the click 5-10 times before it's taken.
2)the main menu looks like the app isn't focused. text is gray on white as opposed to the black on white of any other GTK2/3 app on my system.

We're dealing with a hell of a problem here.

I'm here for any other test you can think of guys, in the meantime thank you.

Comment 8 Christoph Feck 2020-10-21 20:16:58 UTC

New information was added with comment 7; changing status for inspection.

Comment 9 David Edmundson 2023-09-06 10:38:09 UTC

This bug was reported against an outdated version of KWin. We have made many changes since the. 
If the issue persists in newer versions can you reopen the bug report updating the version number.