How do you clear the selection?
I tried to use the one on the original post, but I cannot figure out how to make it work. As a test I tried a script and run as noted by the OP.
del self.props.get('selection').get('active').get('data')[-1]
I also tried manually seting the property to [] or 0, but If I am not mistaken thats readonly.
self.props.selection.active.data = []