If claws can't connect to the network, or if the server changes its certificate (like gmail certificate rotation), it will show a focus-stealing dialog. I'm observing this on X11 under IceWM. It will show the message dialog on the currently active workspace (even if it's not the workspace claws is on), and will steal keyboard focus. This is extremely annoying and claws absolutely shouldn't do this.
How your window manager presents dialogs and handles window focus is completely out of control of claws-mail.
How come claws is the only program that exhibits this behavior? Maybe you're using a hint you shouldn't be using.
There is a hidden preference to allow rotating certificate problems to be ignored, I forget the exact syntax but it does work. I assume that when a real certificate change occurs you want to be able to check it. I think this works, it certainly does for me.
(In reply to comment #3) > There is a hidden preference to allow rotating certificate problems to be > ignored, I forget the exact syntax but it does work. That's the "live_dangerously" option. It's global though. There's now a per account setting (SSL - Automatically accept unknown valid SSL certificates)