If you right click a thumbnail on a contact sheet, you can see from "Catalog info" the catalogue(s) in which an image is included: entirely as it should be.
There are two other right click menu items: "Include in catalog" and "Remove from catalog". The menu state does not indicate whether or not the selected photo is, or is not, in any particular catalogue. Moreover, clicking "Include" seems to add the image to all the catalogues which have Add/Modify enabled, and "Remove" removes them from all catalogues, whether or not they are active (Add/Modify enabled or not).
If an image is not in any active catalogue, the Remove option should be greyed out, because it is (or should be) meaningless in this situation. If the image is in more than one catalogue, then selecting "Remove" should open a tick box which allows you to select the catalogue(s) from which the image should be removed.
In similar vein, if an image is already in all active catalogues, the "Include" option should be greyed out, because it will do nothing. If it is in none, or some but not all of the active catalogues, again there should be a tick box which allows you to select the catalogue(s) into which you want to add the image.
Also, should these two menu options be limited to active catalogues, those with Add/Modify checked? To my mind, it is not expected behaviour that choosing an action from the right click menu on a contact sheet should operate to add to or modify the contents of a catalogue that you have not marked as being subject to modification.
Is there any reason why it does not work like this, or should not work like this? Or have I misunderstood how it works?
Graham