repair block data change undo

engine/api.py

@@ -896,9 +896,10 @@ def changeBlock(blockId, newParametersDict):
     """for example "name" or "minimumInTicks"  """
     track, block = session.data.blockById(blockId)
     moveFunction = _createLambdaMoveToForCurrentPosition()
+    oldData = block.getDataAsDict()
     def registeredUndoFunction():
         moveFunction()
-        changeBlock(blockId, block.getDataAsDict())
+        changeBlock(blockId, oldData)
     session.history.register(registeredUndoFunction, descriptionString = "change block")
     block.putDataFromDict(newParametersDict)
     callbacks._updateTrack(id(track))