Question:
I have made an MDI application with many MDI children, but when I try to close an MDI child it becomes minimized. How can I avoid this and close the window?

Answer:
To completely close an MDI child form, do the following:

1. Display your child form in the IDE, making sure you’re selecting theform itself, not one of its components (hint: look at the ObjectInspector to see if the currently displayed component is actually the formitself).

2. Click on the Events tabs of the Object Inspector.

3. Double-click on the OnClose event to open a handler for it.

4. Type the following in the begin and end block:

 Action := caFree;