Folks, I will be shortly submitting an updated tomboy-ng to debian and
will close this bug at that time. So, better explain my position.
The 'bug' is not really fixable from my end I am afraid. Firstly, it
only shows up under Wayland and even then can be worked around with
either an environment variable or command line switch which tells the
Qt5 framework to avoid Wayland.
The default install of tomboy-ng installs a desktop file that ensure
tomboy-ng uses xcb and if used that way, the problem does not show up.
So, starting through the menu system, no problem.
If you start tomboy-ng from the command line, without either the
necessary env var set or a switch (-platform xcb) you will experience
the noted problem and several others. I hope that at some stage,
Wayland will work somewhat better.
Further information is available on the tomboy-ng wiki, Bugs and Know
Issues page -
https://github.com/tomboy-notes/tomboy-ng/wiki/Bugs-and-Known-Issues
Thanks for your report.
Davo