Selected group item - How should collapsed group indicate selection?

Question

Requirements:
. selectable groups and items
. click on the arrow expand and collapse groups
. click on row selects the item or group
. click on group row select all items within

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My question is: When you select some items within the group and you collapse the Group, how should you indicate that group has selected items? If you indicate the group has some selected items the same way you indicate the whole group is selected it could cause confusion?

Answer 1

You could try using the same approach Eclipse uses (or any other Java program I guess).

They're using checkbox to indicate that all elements of the group are selected and a --symbol if only some of them are selected.

Nothing selected

All selected

Not all elements selected

One plus is that it's easy for the user to (un-)select the whole group.

Instead of the checkbox, it might also be possible to work with colors or symbols. This could also work if you're having more than two levels, while the checkbox doesn't.

I can also imagine adding the number of selected items and/or the number of available items to the top-level.