Description:
I updated to Qt 5.15 a few days ago and I notified there's an issue with the mouse input there. I got a slight mousewheel scroll up when I do the right click and I got an erroneous response when I do a click and drag the mouse, when I release it, it doesn't respond as it should.

I detected this using KDE Connect virtual remote touchpad, on Telegram Desktop, selecting messages from any chat.

Additional info:
* package version(s)
Qt 5.15
* config and/or log files etc.
I use Plasma Wayland session, maybe it has something to do with that.
* link to upstream bug report, if any

Steps to reproduce:
1. Have Qt updated to 5.15.
2. Login to Plasma Wayland session.
3. Open Telegram (I detected the bug with this app).
4. Use KDE Connect virtual remote touchpad as the mouse input.
5. Try to select messages from any chat, using the click and drag to select multiple messages or right click to do the forward or select message.