For one place in our application, a ListView is used along with checkboxes, but it seems like it would be good to be able to use tri-state checkboxes here, such that a mixed state could be indicated for some entries. But, then the question becomes: if the checkbox is mixed, is it checked or not? Two thoughts on that:
1. Add a method to get the checkbox state for all items, so you can check yourself if they are checked, unchecked or mixed.
2. Add a property "mixedAreChecked", which if set true (default false) would make the mixed state entries show up as checked.
Also, how do you set the "mixed" state for an item? Not sure about that yet.
Altogether: lots of implications throughout the code to support this feature.