LCDNumber

Can you run in the terminal:
designer -qt=5

It might give some clue of the problem.

when I enter
designer -qt=5
in the terminal, the application opens immediately without any comment

/usr/lib/python2.7/dist-packages/qtvcp/plugins/qtvcp_plugin.py      ->      ~/.designer/qtvcp_plugin.py

Should be:
->  ~/.designer/plugins/python/link-to-qtvcp_plugin.py

maybe this helps? (for 2.
github.com/LinuxCNC/linuxcnc/tree/2.8/lib/python/qtvcp/designer
 

thank you, Chris, tomorrow I have to get up very early, but after that I will be very happy to continue, we will surely find the solution very soon

I'm back here, Chris, I changed from an iso LinuxCNC 2.8.2 installation to the following, is this okay?

Buildbot Packages List
Master branch (development - 2.9)

Buster (arch: amd64)
uspace: realtime with RT-Preempt, and simulation
deb      buildbot.linuxcnc.org/ buster master-rtpreempt
deb-src buildbot.linuxcnc.org/ buster master-rtpreempt

and then to install designer qt5 in master, how should i do this?

For linuxcnc 2.8.2, I do it as in the attached instructions. The script did not work for me.

thank you that looks good I'll try it out and I'll let you know

In master branch there is an updated script:
linuxcnc.org/docs/devel/html/plasma/qtpl...c.html#qt-dependency
 

Linuxcnc 2.8.2 not working after upgrade lcdnumber. Please tell me how to fix it. Sorry, I already corrected it with the help of the designer.

unfortunately, I don't have it at hand at the moment, but I'll be happy to deliver it later here, of course