yugutou Thanks for your report! However, I think the current behavior is quite smart. If you look at the selection in the viewport, you will see that when the attachment is hidden, the selection on the viewport has already moved to the parent bone. So when the items displayed in the tree view are updated by the filter, they match the contents selected in the viewport. Does the current behavior interfere with your work? When do you have trouble?

yugutou Sorry it took me so long to notice, but this is the same topic we discussed before:
https://esotericsoftware.com/forum/d/26209-grid-selection-problem/

As Nate answers there, you can now switch whether or not the tree view selection changes depending on whether or not the Auto scroll button is turned on. When Auto scroll is on, it will match the selection in the viewport, but when it is off, it will maintain the previous selection, as it did up to version 4.1.

yugutou Hmm, that's weird. If you turn off Auto scroll, it should work as shown in the following video:

For your information, even if you turn off Auto scroll, you can still use the hotkey / to scroll the tree view to the currently selected item, as shown in the video.