■ Only one form within your project can be specified as MDI.
■ Possible solution:
• If you tried to change the MDI form, you must first set
the original MDI form's FormType property to 0 - Normal.
Then set the new form's FormType property to 1 - MDI.
■ If you need additional help, move the cursor to a keyword
and press F1 to open the Help window.