Jenner,

thank you loads, this problem was driving me mad. I dont usually ask for help unless am stick.
My original code is working as it should with the mdi container and parent but you posting the new project got me thinking of testing from scratch again.

Guess what the problem was...nothing to do with containers, nothing about form properties, nothing else but I had

Code:
MenuStrip1.Focus()
when the main app loads...(my app uses menustrip instead of buttons)...

Not quite sure why focusing the menu strip before loading the forms was causing it not to work. Perhaps it because its passing control to the menu strip which then becomes the parent???

Anyways point is, its working.

Cheers