improved version of my d3.js selection frame example (https://gist.github.com/lgersman/5310854) supporting draggable/selectable nodes

• Click into the drawing area to start the selection frame
• move the mouse to resize the selection frame
• Release the mouse button to resize the selection frame

new features :

• circles are draggable
• circles can be selected (multiple selections possible by pressing CTRL while clicking a circle)
• the selection frame selects all circles within the frame (by pressing CTRL the selected circles will be appended to current selection)
• multiple selected circles will be dragged simultaneous

See it live : /lgersman/5311083