You’re right, but sluggishness is only part of the problem. I’d be fine with it if all panes in the tool behaved like a browser pane should but expected controls for browser panes and collection controls are not implemented, or are implemented inconsistently. And as I mentioned before, the orange “charm” to indicate updates is horrible if you have more than a few dozen items in your library. Items with updates really should either be sorted to the top of the pane or added to a separate list control.