I am trying to copy over a running Thunderbird from 42.1 to 42.2. I have copied over the program profile stuff plus the mail folders and when I run it it all works except there are no window borders and so no minimise/maximise/close buttons because there is no title bar. Now on the 42.1 system this all works as expected but on 42.2 this happens. I have also copied over the working Firefox setup and that works OK with borders and title bar as expected. Both systems run KDE so I expected it to work.
How can I get the borders and title bar back please? Thunderbird is the only application where this is happening on the 42.2 system, all other application windows operate as expected. I have a second user on this system and everything works as expected on that user.
Stuart