<blockquote>Locking duplicate thread.<br> Please continue here: [/questions/826471]</blockquote><br> If I drag the FF window partly offscreen, the content shifts within the window, as if it is aligning to the edge of the monitor, not the edge of the window. To reproduce using this page: Drag it half-way offscreen on the right edge of the monitor. The content is dragged at first, then suddenly jumps back to the original position, showing the large white margin that's on the right edge of the page, and leaving most of the page invisible. No scrollbar appears. Positioning of the cursor seems messed up: if I click on the dropbox arrow just below, nothing happens, as though it doesn't think I clicked in the right place.