> It blows up quickly when Smart Splitters is turned on

Right, I did not consider smart splitters.

We just need to add a guard in #repositionBy:

	self setProperty: #fullDelta toValue: ((self valueOfProperty: 
#fullDelta) ifNil: [0 at 0]) + delta.


And, no, smart splitter do not fix the bug I'm addressing here.

Stef