this problem occurse since today and I'm working with version 1.3.46.
When I want to edit one of my missions or even when i try to add a new mission in my campaign, it simply goes back to campaign selection instead of opening the mission editor.
I even tried creating new campaigns and importing everything there, but the same error occurs.
Only thing that lets open the mission editor is restarting the game, creating a new (empty) campaign and then the edit mission button works. But if i go back outside the campaign and reopen it, the error occurs again.
I also send a email with the according campaign, maybe that helps.
I tried to check the files of my installation via steam, but that didn't helped at all.
Thanks in advance for any help.