Very useful extension.

And personal opinion ----

On the subscription page.

If only want to see one group at a time.
When switching from one group to another.
On/Off button operation is very troublesome

The group at the top directly switches to single-select mode or multi-select mode.
Instead of giving each grouping to a On/Off button.
That would be better.

In this way (on single-select mode), when switching a single group, only one click is required to complete the operation.

forgive my poor English & thx for ur job.