Setting the text origin on a node to null will cause an exception in the scene graph synchronization code that is unrecoverable.

Run the attached test case, click on the window (the MOUSE_CLICKED handler will set the text origin on the text node to null) and see the NPE. If you move the mouse within the window you will get continuous NPEs after that. Note that the test case tries to set the origin back to a non-null value on a second click, but the event code is unable to process any more events due to the NPEs.