I have found the problem with my textboxes not doing Copy/Paste/Cut/SelectAll from the keyboard shortcuts Ctrl+C, Ctrl+V etc

When the textbox is placed on an MDI Child form, the form seems to do something to prevent the event reaching the control, meaning that while copy and paste from kayboard shortcuts work on any control not on an MDI child, they dont work when the form is MDI

How do i investigate and cancel out or disable this behaviour? Not being able to cut/paste in textboxes is very annoying!
Matt