Indeterminate checkbox state

[jes708]

When a checkbox has child checkboxes which are checked, that checkbox should have an indeterminate state to signify that some of its children are checked. This is especially important if the parent checkbox exists as part of an accordion, and the accordion is closed, yet some of its children are checked.

In this image, SUV should have an indeterminate state.

This image shows an example of an indeterminate state.

[dansternfeld1]

Nice idea, @jes708!

A few thoughts I'll throw out there:

• It should probably apply specifically to a "mixed-checked" state; if all sub-options are selected, the parent checkbox should just be checked, and if none are selected, it should be unchecked.
• It might be worth making the new mark an intermediate color if it works visually & improves the legibility of this new state.
• I think a prop would be needed to determine whether to check or uncheck all child boxes when clicking on a parent checkbox that's in this new state, as I could see valid use cases for either approach.