No replies, so I'll try to answer my own questions

(X3e Producer; wondering if the same is true for 2015):
1. Alt+Shift+H doesn't work as a toggle. If you select a collapsed folder and press Alt+Shift+H, the folder will be expanded. However, if you press Alt+Shift+H again with that same folder selected, nothing will happen. However, if you start by selecting an already expanded folder and press Alt+Shift+H, the folder will collapse and the first track in the Track View will be selected.
2. There's no way to expand/collapse all folders with a single command (that I've found.)
3. SONAR doesn't show the length of the current selection anywhere, whether it's From to Thru or the Loop Selection or what I'm currently drag-selecting.
-Susan