Fix X11 modifier bug for mouse input.
Fix X11 modifier bug for mouse input.

stevenlovegrove/Pangolin,wxdzju/Pangolin,randi120/Pangolin,pinglin/Pangolin,wxdzju/Pangolin,randi120/Pangolin,mp3guy/Pangolin,renzodenardi/Pangolin,pinglin/Pangolin,visigoth/Pangolin,tschmidt23/Pangolin,arpg/Pangolin,tschmidt23/Pangolin,mp3guy/Pangolin,stevenlovegrove/Pangolin,stevenlovegrove/Pangolin,tschmidt23/Pangolin,visigoth/Pangolin,renzodenardi/Pangolin,arpg/Pangolin,mp3guy/Pangolin