I started writing this the other day but gave up because I wasn't sure what caused this to happen. I'm still not positive, but I have a better idea.
I'm running Notes 8.01 on Windows XP SP2. If I turn on the LotusScript debugger, go to my client and open a composite application, like my mail database on the 8 template, I get a debugger window. So far, so good. If I say "Oops, I didn't want the debugger for that" and click the Continue button, the debugger is replaced with a window of my first mail message. That has a title bar and a menu bar but no toolbars, and there is no way to make it go away. I have to kill the client processes and restart to fix it.
This only seems to happen (so far) with a composite app. And I haven't done exhaustive testing (because I'm trying to get my projects done!) to know if there is something specific that is a trigger or if it is just something weird about my installation (see my last post for Sametime oddities).
I'd be interested to know if anyone else can reproduce this problem.