Error: Cannot focus a disabled or invisible window.

[jamie]

There is a lot of strange but true coding going on around here!

Is there is possibility of multi-threading taking place?

[KodeZwerg]

Code: Pascal  [Select][+][-]

1. frmEditMC := nil; // optional

I don't know how many times I must say this. "FreeAndNil" does exactly what you are doing in with one call, not two separate calls.

There is no need to nil at all, thats why I wrote "optional", or do you see any "if Assigned()" checks in his code?
As long we see nothing else beside his calls to show a formular, this all is just mumbo jumbo and wild guessing.