Multiple issues with the 'Find' dialog

I get stuck with a couple of issues with the 'Find' dialog that I can't replicate/trace very well (even with the Java console opened).

'Find':
stops working completely (I cannot write into it anymore)
doesn't come up with ctrl-f
highlighted regions found disapear if the mouse pointer quits the dialog.

I encounter a similar problem with the keyboard functions where everything stops working (arrow keys won't move sequences, etc.), sometimes resumes sometime I have to restart Jalview.

What could I do to be more specific on these issues and have you experienced such issues ?
I'm thinking of a memory allocation problem... (?)

Thanks,
Richard