'debugger' called from the right-hand side of IDE panel?

Hi! I think this might be because you're uploading to RAM: http://www.espruino.com/Saving

Basically, when you upload to RAM, code is executed as it is uploaded. If you have a debugger statement in your code then Espruino would break out into the debugger before all the code had finished uploading, so it gets ignored.

As @Robin says, if you execute the code after a delay with something like setTimeout(testDebugger,1000); then it'll execute after the upload has finished and you should enter the debugger just fine.