If the user double clicks a specific node, it should change the heading of that node, rather than always changing the last one
It would also be nice if when adding a new node its heading is only changed when the user double clicks, and with a single click the node moves instead, which would solve these two issues:

• If the user adds a new node it's easy to accidentally move the cursor slightly, which changes the heading
• If the user wants to move a node they just added, they have to release the mouse and click again
  For me atleast the first issue is more annoying because it happens more often
  An added benefit is that the app is more consistent since clicking once is always for moving and clicking twice is always for changing heading