Hide application menu bar
You can make the menu bar of an application hide automatically by adding this to the Info.plist:

&lt;key&gt;LSUIPresentationMode&lt;/key&gt;
&lt;integer&gt;4&lt;/integer&gt;


Windows can't be moved over the freed up space though.

If the application is signed, modifying the Info.plist invalidates the code signature. It also makes sandboxed applications like TextEdit and Chess crash on launch.