Comment 0 for bug 1576605

This bug applies to all Firefox versions since Unity brought global menus. However, only Firefox is affected, I've not observed any other app with a similar issue.

What I expected:
 * Activating a menu item to simply display the relevant menu and cause no further interface changes

What happened instead:
 * Activating a menu item displays the relevant menu and introduces a space between the titlebar and tabs

The change is persistent as long as the window is open. Resizing or maximizing makes no difference. Enabling and activating menus from the title bar causes the exact same effect. Closing the window and reopening it from History's "Restore Closed Windows" removes the space. In other words, it does not affect newly opened windows.