Tree error while dragging nodes

SmartClient Version: v9.1p_2014-06-14/PowerEdition Development Only (built 2014-06-14)

browser Chrome, Safari, Firefox on Mac OSX
IE11 on Win7

please open a '_Trees_Dragging' sample from the showcase, and try dragging a node.
You'll see a 'Uncaught RangeError: Maximum call stack size exceeded'