In buffer B, I press C-x r SPC r to store the position of point.
I switch to buffer A and do some work. I then press C-x r j r to return to the position I saved in buffer B.
How do I get back to the position I left in buffer A? The following do not give the required result: C-x C-x, C-u C-SPC or C-x C-@.
My understanding is that C-x r j r will push the position onto the global mark ring and that C-u C-SPC will take me back there.