Getting Title/Caption of program mouse is focused on

What i am trying to do is have:
text1.text = (Caption of current program the mouse is focused on/clicked)

Example:
Text1.text = Mozilla Firefox

Also i need to know how i could send a message box after the textbox has 20 characters in it.

Sorry if i didnt explain this enough, i didnt really know how to explain, I hope you understand

Thanks, iTHUG

The WindowFromPoint API returns the handle of the top-most window at the given position on the screen.

Thank you very much :D