Ouch ! The problem appeared again for me, but in a different way.
I had only one writer document opened, moved it from one workspace to another, did many different things for one hour, and then I could not switch from Firefox to LibreOffice. I had to minimize Firefox to see Libreoffice. In the mean time, I tried to clic on the LibreOffice icon, but nothing happened.
Unfortunately, I couldn't reproduce the behaviour.
Ouch ! The problem appeared again for me, but in a different way.
I had only one writer document opened, moved it from one workspace to another, did many different things for one hour, and then I could not switch from Firefox to LibreOffice. I had to minimize Firefox to see Libreoffice. In the mean time, I tried to clic on the LibreOffice icon, but nothing happened.
Unfortunately, I couldn't reproduce the behaviour.