Comment # 17 on bug 1221515 from Olivier Belleux

(In reply to Fabian Vogt from comment #14)
> Those packages are a hard dependency of plasma6-workspace, it's not possible
> to install without those. Do you have any zypper locks defined or not set
> the repo priorities appropriately?

Hello, 

I've just upgraded and everything went well.

This confirms that the culprit was Texmaker, since uninstalling it results in a
different - and above all functional - resolution of the upgrade.

Strangely, when I tried to reinstall texmaker from my repositories
(https://build.opensuse.org/project/show/home:Wolfheri:Qt), it was the only
package selected. 

Perhaps this bug is due to the way the spec is written?

Thank you for your reply and your question, which have enabled me to look at
this problem from a different angle and solve it.

As far as I'm concerned, this bug is resolved. 

Have a nice day.