I use folders extensively. With some having subfolders etc. However I’ve found that Cubase deals very poorly (even crashes sometimes) when I try to open folders and parts not in folders simultaneously into the editor. Most times all parts will show up, but when I go to make an edit, everything in the non selected type (either folder or non folder) will exit out.
Example:
I select a folder track with five bass parts, I also have a string part, not in a folder selected.
I go to edit.
All open in the editor ok.
Once I try to make an edit to the string part the bass parts disappear from the edit view.
Very annoying. Only workaround has been to create folders for everything and open them together.