Patch for bug ID 3598585 posted here: https://sourceforge.net/tracker/?func=detail&aid=3598585&group_id=588&atid=100588
The reason for NullPointerException wasnt specified well. The real problem was, that if user wanted to add new tool to toolbar and forgot to select an action to be performed by the new toolbar icon, then the NullPointerException occured, but the user didnt see any action. It could be quite confusing.
My simple patch gives the user more info, when he forgets to select an action and presses the OK button in toolbar Add dialog.
When user presses OK and action is not selected, the message dialog appears and warns him.