Bug 387182

Summary:	Scrolling bug with KDE/QT apps, but not with GTK
Product:	[I don't know] kde	Reporter:	Jacob Emery <hmpl>
Component:	general	Assignee:	Unassigned bugs <unassigned-bugs-null>
Status:	RESOLVED DOWNSTREAM
Severity:	minor
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Jacob Emery 2017-11-21 13:30:29 UTC

I have a laptop that I sometimes connect to an external monitor. I had frequent crashed with the external monitor until I changed from OpenGL 2.0 to OpenGL 3.1 in the display settings. Although this is not the reason I am filling this bug report, maybe it could be advised to people that report problems with external displays.
That solved almost all problems, but there is only one left now. It is weird because it happens only on the laptop and only with KDE applications (maybe QT in general), but not with GTK applications. The problem happens with both OpenGL 2.0 and OpenGL 3.1. I didn't test it on wayland. I don't have a complete scaled display, but my fonts DPI is set to 120. I'm using KDE neon 5.11.3.
The problem is: if I scroll with the touchpad or with a mouse on Firefox, it scrolls normally. But if I change application, let's say I click on Okular and I want to scroll, as soon as I start scrolling it goes one page back (so it doesn't start scrolling from where it should be supposed to start), and this is becoming very annoying. If I go back to Firefox again, it will work all right, and if I go back to another KDE app it will start scrolling in a weird way.

Comment 1 Jacob Emery 2017-12-01 09:41:21 UTC

I solved it by installing the latest libinput for KDE neon, so by running:
sudo apt install xserver-xorg-input-libinput-hwe-16.04
Although the default synaptics driver for the touchpad will be loaded like before, now I don't experience the bug any more.