After working with VS for years I only just noticed that it is possible to split a code window into two panes !
Of course it would be even better if you could continue the splitting process into multiple panes but even having two is useful where, for example, you want to track two methods in the same file. It would also be even better if the debugger would recognize if stepped code was already visible in another pane and switch to that automatically

If I missed that then I wonder what other useful facilties I might be missing?