[Pharo-users] mouse buttons in Linux, deleting certain morphs

Hi list. On a Linux host with default mouse mappings in X ( "Button Left"=1, "Button Middle"=2, "Button Right"=3 ) is there a setting to enable the Right Button as blue button without requiring the control key ? Regardless, I'm unable to delete certain morphs ( e.g. RectangleMorph, EllipseMorph ) in the World using the CTRL right-mouse button. To reproduce create a RectangleMorph in the World and try to delete interactively. Sven