User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0 Build ID: 20120420145725 Steps to reproduce: This bug ( I guess it is a bug ) exists since a lot of versions 1: I open firefox in a windows that is let us say half the height of my screen 2: I created a bookmark folders with quite a lot of entries 2: I open the bookmark folder and because of the large number of entries, the popup subwindow showing the bookmarks is longer that the firefox window itself 3: I click one of the bookmark entries in order to go there 4: I close firefox ( extra step for demo purpose) Actual results: Firefox went to the page corresponding to the bookmark entry I selected but the extra long part of the popup showing all my bookmarks entries remains on the screen ( I can erase it easily but it should disappear when the popup closes) Expected results: The popup subwindows of the bookmark folder should have disappeared entirely , not only the part showing on firefox windows but also the one that is under In fact the propup disapears only on the firfox windows , but what is outside does not