If I create a mouse gesture it leads to a strange behavior of the scroll function in almost all applications (except thunderbird and firefox).

When I do the following:
1. I scroll down to the bottom for instance in dolphin.
2. I press the gesture mouse button and release it. (just press, no gesture)
3. I press the left mouse button somewhere in the same window and release it.
4. I use the scroll wheel to scroll down one notch ...

What then happens is:
The application doesn't scroll down but instead scrolls up to the very top!
Very disturbing!

As soon as the gesture is disabled, the behavior returns to normal.
The same happens if I just install Easystroke. Just the installation (without any gesture created) leads to the same problem.

Does anyone have an idea what's going on here?

I love KDE and use it for many years. But I need the gesture functionality. I would hate to need to leave KDE just because of this! Please help!

Greetings from Germany!

PS: I am running Linux Mint 18.2, KDE-Plasma-Version 5.8.8, KDE-Frameworks-Version 5.36.0, 32 bit

EDIT: I just found out that Thunar too is immune to this problem. So its thunderbird, firefox and thunar, which are unaffected.

In my eyes this is quite a problem!
Does anyone have an idea?

I would like to report a bug on this on https://bugs.kde.org.
But what product should I report it to?
Because Dolphin is affected, Kate, Kwrite, ... seems like all native KDE-programs are affected.

Turned out to be a Qt-Bug:

https://bugreports.qt.io/browse/QTBUG-49294