Bug 495957

SUMMARY
When drawing or writing in Xournal++, there is a delay in drawing or writing output

STEPS TO REPRODUCE
1. Select the pen tool
2. For better viewing Edit --> Preferences --> View --> Cursor icon for pen --> Big pen icon
3. Using the stylus or the left mouse button, draw a line from left to right. To make it more noticeable, it is worth doing it more sharply. Or you can try writing. 

OBSERVED RESULT

It becomes noticeable that the line that remains when drawing or writing text appears with a delay after the pen movement.

EXPECTED RESULT

What is written or drawn should not be displayed with a delay. I would like it to be smooth as when writing with a pen on paper.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: Kubuntu 24.10
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.6.2

ADDITIONAL INFORMATION

This behavior is observed with Plasma 6. I use Kubuntu, but I did the test in KDE Neon, which already has Plasma 6.2.3. In the live session, the behavior is the same as described above.
For comparison, I downloaded a live session of Ubuntu 24.10 (Gnome, Wayland).
The described problems are not observed.
So, this is a bug in KDE (KWin) Wayland.
Thank you.