I have become a big fan of the safe delete "stacked operation". When I'm at a specific method I run "safe delete". For each usage that pops up in the "usages" window I just run safe-delete on each usage again. Repeat until you manage to delete something.
At some point I will have a large number of "safe delete" windows open, and I can rerun safe delete to close each of them in turn. If I'm lucky I will be able to delete the method in the end.
This "stack" of windows is really neat, and someone showed me this technique some time ago.
I also use bookmarks as a "kind of" stack when analyzing code, I will simply set bookmarks 1,2,3 etc to point at relevants pieces of code in my analysis. This also represents a kind of stack, since they mark breadcrumbs in my train of thought.
Anyone have any other nice "stack" like features they know of in idea ?