By clicking on "End",it doesn't kill the programs sometimes. But I want a way to completely kill it with something like xkill.
You can do that by right-clicking on a process -> Send Signal -> Kill. Please be reminded that you still have several bug reports in NEEDSINFO status - we hope you can provide the requested information as soon as possible. (I observed that you have been filing new bug reports nearly every day, but is not responding to NEEDSINFO requests.)