Textboxes and shortcut keys

[H. Blijlevens]

I've been debugging an application of a former colleague, and some things
aren't working as they are supposed to.
It's an MDI based application with 1 empty MDI Child Form as a template.
For each MDI Child Form he built a control containing all the GUI elements
for that base MDI Child Form: Panels, Labels, Listboxes, Textboxes, etc.
Quite unusual, but we are in need of the functionality and rebuilding is not
an option.

The problem is as follows:
using the Delete key anywhere on the main form (Parent MDI Form) causes the
application to hang (CPU usage >= 97%). This happens only once; after using
Ctrl+Esc or Ctrl+Alt+Delete the situation is normal. (By the way, KeyPreview
= True, but entering the Delete key and the hangup of the application
preceed the KeyDown event)

Still, I can't use the Delete key for removing text from textboxes (only
Backspace). Neither can I use Ctrl+C, Ctrl+V or any other system shortcuts.

Any help in this would be appreciated!