`context.emit` does not remove wrappers

[saraedum]

In the graph-editor example, the following workaround is necessary, since the wrappers otherwise do not get removed from the list correctly:

     def stopdrag():
         nonlocal dragged
-        context.emit('dragged', dragged.value, pos.value)
+        context.emit('dragged', dragged.value, pos.value[dragged.value][0], pos.value[dragged.value][1])
         dragged.value = None