I have searched the forum first before posting this and don't see this problem reported. I had v2.23 now have latest 2.28 and both exhibited same problem, prev versions were ok. OS is WinXP 2002 service pack3.
After a few minutes use I can no longer select any tabs nor menu nor select an URL. Url Snooper is stiil working however and continues to log net activity. Strangely I can still get a right click menu so can using this, select all urls then paste to clipboard, copy to notepad and select one I want and then clear. So have a workaround. I used to kill the process every time this happened but on repeat launches it often locks immediately.
If anyone has suggestion to fix then thanks, else this post "lose mouse focus" may help others with same problem.