creat instanc dn argo tree dn explor tree add tree select listen dn tree select listen drag sourc drag sourc drag sourc drag gestur recogn fire event respons drag gestur compon drag gestur recogn dgr drag sourc creat drag gestur recogn dn constant action copi specifi valid action elimin right mous click valid action dgr set sourc action dgr sourc action input event button mask argument compon associ target second argument drop target listen drop target argo drop target listen kei stroke ctrl kei stroke kei stroke control input map ctrl diagram clipboard action action map diagram clipboard action action save diagram clipboard 