why not auto hide menubar similar to panel auto hide?

[harishpathangay]

Hi,
this is a general question in Linux, not specific to CentOS or GNome or any DE.

Is there a functionality where I can auto hide Window Menu Bar?
For Example, the Panel in Bottom of XFCE DE can be made auto hide, it will popup when mouse hovers over the panel area.
Similarly, I am looking for a functionality where Below the Window - the Menu bar can be auto hidden?
Is this possible in any DE currently?

Ubuntu has Panel/Menu Bar Integration. that is not what I am looking for.

Also, if on the window title bar, I can have a button with a down arrow. if I click that menu bar will appear. will close on second click or if menu item clicked.

it will preserve both space and take the same amount of mouse clicks and I need not loose menu bar permanently. some times I prefer menu bar.

things might already be there. if I was unaware of it, please let me know.

thanks,
harish pathangay