Reader 9 linux leaves a small window on top

Been using Adobe Reader 9 on Xubuntu desktops for several years through many updates and upgraded versions of Xubuntu. Love the program and use the fill in forms quite often. Only one problem and can't find a solution. Sometimes when I close a tab there is a small copy of the document that appears on top of the reader and I cannot find a way to get rid of it. Today I had to open about 7 tabs to work on several forms together toggling between them. When I close a tab it left the annoying small copy of it on top. Click on it, rite click on it, nothing obvious as to how to close it. Had a deadline to meet and needed to open tabs, close others, etc. all day. By late afternoon I had half a dozen of these small versions of then closed tabs all over my screen to the point I couldn't see my work. Had to drag the reader around the screen to find a way to work on the forms.

What am I doing wrong?