A few versions ago (donʼt know exact one) a new effect appeared: when pressing right mouse button on an element to get its menu (standard Firefox menu, not overridden by the page), if mouse cursor position is over a popup menu item, this item is immediately selected on mouse _release_ button. In most cases the context menu popups right to the mouse position and this causes no effect. But if there is no place to right (the selected element is near right screen margin), a menu item appears under the cursor and, as stated above, is selected. It is unpredictable what item will be selected. This is rather controllable (although annoying) with real mouse but uncontrollable with touchpad, as on most laptops. Please suggest how to disable reaction on the mouse button release.