F8 bug?

I’ve encoutered this problem a couple of times already:

When you have 2 custom panels installed (like the NetDebugger and Service panel for AMF-PHP for example), everything works fine. You select the panel, do what you have to do, done.
When you install a third panel, you’re NEVER going to see it working. When you select Window > other panels > myPanel, you don’t see “myPanel” popping up, it’s alyways one of the previous installed panels. Which is, as you can imagine, not amusing.

Is this a known bug / issue? Or does anyone have a solution for it?
Thanks very much!