copyq problems

In you have linux, flatpack installation of copyq can solve many possible problems, but it has also some disadvantage.

The best choice, then, is to install copyq according to its website:

Ubuntu and Debian users can add the official PPA:

sudo add-apt-repository ppa:hluk/copyq
sudo apt update && sudo apt install copyq

In same cases it could be not enough the above code. Then you can try with something like:

QT_QPA_PLATFORM=xcb copyq

You can set permanently in KDE menu with a config like in the below image

Calibre unexpected dark theme

It can be very annoying an undesired dark theme in Calibre (both viewer and editor): reading could become difficult, or almost impossible.
This happens (probably) if you have a flatpack release of Calibre: try to remove the flatpack one, and install a release of Calibre from their website.

Flatpack is convenient (automatic updates), but have some problems….

Flatpack and the space of the hard disk

Flatpack has the big advantage that you can a) run apps that couldn’t run the “normal” way (integrated with the system), because of lack of dependencies or b) have automatic updates of apps otherwise upgradable only via ppa or manually.

But its big disadvantage is the space occupied on your hard disk: indeed any app in Flatpack is a “world” in itself, regardless not only of the system, but also other apps in Flatpack itself.

Therefore, be careful to add Flatpack apps, unless you need really them (and them via Flatpack).