#606 Suggestion for deletion mechanism

[Hal Crichton-Standish]

Currently, to delete multiple items on the screen, you have to drag the mouse over your selection before hovering the mouse over individual items and pressing the 'delete' key. Also graph plots need to be deleted separately with a right click as the other method doesn't work for them. Perhaps it might be possible to be able to delete a selection of items after dragging the selection box over them.

[High Performance Coder]

Done in Minsky-1.x and master branches.