In Fullscreen, disable auto-hiding Mac menu bar (on latest Mavericks)
While in VirtualBox (Ubuntu) fullscreen, on a Mac host, each time the mouse goes near the top, the Mac auto-hide menu bar appears - and I want to prevent that, or at least, since it's the annoying component, reduce the time it takes to that menu to disappear when the mouse goes down [currently it's ~1 seconds].
Ideally the time needed to trigger that menu should be higher than currently [instant] - eg like keeping the mouse on top for 1 whole second.
Illustration below shows the Ubuntu menu that has been overridden by the Mac menu when the mouse hits the top of the screen.

There are already a few questions like this one that are either old or not answered.
Any progress in Maverics, near 2014?
So it seems someone found a working solution, at last.

First,


close your VMs
Quit VirtualBox


then as root (or sudo ...) 


copy the file somewhere as backup, then edit (eg vi) /Applications/VirtualBox.app/Contents/Resources/VirtualBoxVM.app/Contents/Info.plist
and add the line shown in the middle


the line &lt;key&gt;LSUIElement&lt;/key&gt; &lt;string&gt;1&lt;/string&gt; to be inserted between LSCanProvideIMVideoDataSource and NSHighResolutionCapable

&lt;key&gt;LSCanProvideIMVideoDataSource&lt;/key&gt;    &lt;true/&gt;
&lt;key&gt;LSUIElement&lt;/key&gt; &lt;string&gt;1&lt;/string&gt;
&lt;key&gt;NSHighResolutionCapable&lt;/key&gt;          &lt;true/&gt;


save, then start VirtualBox again (I didn't have to log out/reboot).

The VM will not show anymore among the opened apps icons, but you can double click the VM in the VirtualBox to switch to it.

The whole post by Maestro is here.