[Question] Pen not working on OpenBoard stable + Ubuntu 24.04 + Lenovo Yoga touchscreen

[fabioschoen]

I installed OpenBoard 1.6.4 on Ubuntu 24.04 for my Lenovo Yoga 2x1 with touchscreen.
Whenever I use OpenBoard, I can easily write on the screen with my finger. But with the pen (both the original lenovo pen as well as a Bamboo pen) it starts writing, but as soon as the pen stops touching the screen, it gets "disconnected".
If I go back to other opened windows, like a shell, the pen still works. And, after I do some operation like cut-and-paste on a shell, then it resumes working also on Openboard. But just until I stop touching the screen....

Any hint? Is this happening to others?
Many thanks!
fabio

PS: when I start OpenBoard the following messages appear:

QSocketNotifier: Can only be used with threads started with QThread
sAppSettings location: "/usr/share/openboard/etc/OpenBoard.config"
Invalid path data; path truncated.
Persisting document; path is "/home/schoen/.local/share/OpenBoard/document/OpenBoard Document 2024-11-11 13-24-00.075/metadata.rdf"
Wayland does not support QWindow::requestActivate()
Wayland does not support QWindow::requestActivate()
Wayland does not support QWindow::requestActivate()

[letsfindaway]

Not easy to guess what happens here. But let me start trying to interpret the error messages:

QSocketNotifier: Can only be used with threads started with QThread <- Have no idea
sAppSettings location: "/usr/share/openboard/etc/OpenBoard.config"
Invalid path data; path truncated. <- Known, but a warning only. Just irgore it
Persisting document; path is "/home/schoen/.local/share/OpenBoard/document/OpenBoard Document 2024-11-11 13-24-00.075/metadata.rdf"
Wayland does not support QWindow::requestActivate() <- OpenBoard is not ready for Wayland. There are some known problems
Wayland does not support QWindow::requestActivate()
Wayland does not support QWindow::requestActivate()

So my suggestions are:

• Try starting OpenBoard using an X11 session
• Probably try one of my experimental builds of the current dev branch, which are also available for Ubuntu 24.04.

[fabioschoen]

Many thanks for your prompt answer. Meanwhile I discovered the problem is more general than OpenBoard... It seems that the pen is not working properly on Ubuntu 24.04 whenever you go full screen. Indeed, I tried also Xournal++ and it works perfectly until I go into presentation mode, full screen. Might be a Wayland problem
If you have any suggestion, it will be much welcome, of course!

[letsfindaway]

The only idea I have is to check whether it has anything to do with Wayland. So you could try:

• Start OpenBoard in an X11 session.
• Or at least use the Qt X11 backend by setting the environment variable QT_QPA_PLATFORM=xcb before launching the application. You can do so by starting OpenBoard from the command line using

QT_QPA_PLATFORM=xcb /usr/bin/openboard

[letsfindaway]

Ahh, and I just found this bug report for Xournal++:
xournalpp/xournalpp#5852

and especially this comment: xournalpp/xournalpp#5852 (comment)

Bottom line: It is a mutter problem fixed in Gnome >= 46.5, but Ubuntu 24.04 is still on 46.2.