Dan-

>Say Class A is a grid subclass and Class B is a form containing the grid. I go to the Class Browser and open Class B and the close it. Then I open Class A and I get this fatal error. If I open Class A without previously opening Class B I have no problems.

I've been fighting similar stuff using the class browser. Lot's of C0...5 errors in several places. Sometimes double-clicking a line in the debugger to set a breakpoint, and sometimes as you say.

One thing I noticed was that the class browser would drop my available resources to nearly nothing and it got worse the longer I ran.

I was running W98SE. I installed W2K Candidate Release 2 in desperation <s>.

Most of the C0...5 errors are gone. I've noticed that the opening up a class that *used* to cause the error now result in a message that the class is in use. I press okay, wait a beat, and then retry it and it opens fine.

IOW, what you've noticed is very real IMO and I'm kinda relieved somebody else has seen it.

What OS are you running?