pdxdoug:
Adding a little to this - when deleting a product from a category, I’d like to check the category(s) I want to remove the product from rather than having to uncheck the categories that I don’t want to remove the product from.
Note that this can be "arranged", but also understand the likely impact that this would have on capability. In a mark to delete situation, the most likely displayed items would be only those that are currently assigned with some indicator of which one is the master category
With this "configuration", it would not be possible to also move/add the product to another category without going to some other option/place to support adding the product to another category.
Then unfortunately, under the above same "logic", one should not be able to remove the product from a category when handling an "add" to a category. At that point, either all categories would be shown with those currently containing the product "locked" or not displayed and the ability to add the product to other categories only available to those not marked...
Now additional capability for eqach of these could be made available through the use of javascript/jquery to possibly support some sort of drag and drop or "listing" to move from one side to another (linked/not linked), but if nothing else understand the added complexity of each of these options, the effect on capability, the amount of additional code to support and the ways things can go wrong from an operational standpoint both as a user and in continued capability...
The usual thing to further address is what the overall need is, what impact the current setup has in being (un)able to operate.