By default, the addon run automatically, so every time you add or remove a linked collection it will mark that collection in pink, but if you have a lot collections and you see its starts to slow your computer, you can turn off the auto mark option, and only when you press the button it will mark \ unmark the linked collections.

To do so, go to the addon setting, and uncheck the "Update viewer automatically", you will see a new button at the right corner in the outliner, and every time you will click that new button it will update the marks on the outliner.