Merge Menu Bar With Caption Bar?

I got a application with MDI parent and child form. When the children file is activate it will show two rolls of the caption bar. is the image show,how to make the menu bar from the child form to merge with the 2nd roll of the caption bar? Or straightly hide the 2nd rolls of the caption bar. i try to set the form minimize, maximixize buttong to false , and then activate another child form and close it then 1st child will caption bar is hide, but the form doesn't show in maximize as before, even manualy maximize the form is not allow.