In a big catalog it's hard keeping an overview of collections which have already been used for images in one disk folder.
When sorting images into collections (I am in the left pane on the disk folder tree) it would be helpful, when already used collections (inside the selected folder) are displayed below the disk folder, nearby other normal subfolders.
Example for a disk structure:
Pictures
2023-10-01
normalSubfolder1
collectionA <-----
collectionB <-----
2023-10-02
collectionA <-----
collectionX <-----
They should have a different icon or color as normal subfolders of course. And there should be an option to switch this feature on/off.
It would be OK if the collection list is only displayed for the currently selected folder.
This makes it easier to add images of a folder to a set of collections, instead to search in the collection tree for specific ones, over and over again.