1 - I think it should be easy to toggle it on/off because 95% of the time I would prefer to be in the current interface but it would be nice on occasion to switch to it.
2 - For me to use it I would need two trees. One tree would frustrate me to no end while navigating.
3 - top/bottom, side/side. Considering that I want the tree available for both panes the top/bottom approach makes more sense to me but I think it may be easier for most people to compare items if they are structured left/right. But, with a dual tree interface it could be very cluttered unless the trees for each pane are located above/below the main windows.
4 - keep it simple. I see most dual pane implementations go wrong because they clutter things up too much.
5 - It would be nice to be able to select two tabs and then hit a key or right click to open them in dual pane mode. Possibly go back to two tabs when switching away from dual pane.
I gotta get running for now but I still have a bit more to say.
Steve
XYplorer Beta Club