User Guide says that...
When switching to other tools, the selection for the Weights tool is saved. This enables switching to a transform tool, trying out the weights by manipulating the bones, then switching back to the Weights tool to further adjust the weights, without needing to change the selection.
I dont get it, when I switch to any transform tool switching back does not restore any selection, what selection we talk about? the pies? or the bones in the weight view
or it is so intuitive that I don't even notice it