The Steam Client Beta has been updated with the following changes: General Fixed initial display of systray menu showing as black window. Fixed maximize/restore button and window resize grip not updating properly. When marking a game as private, DLC for the game will also be marked as private. Privacy settings for individual DLC can now be managed from the game's properties, under the privacy tab. Fixed "My Games" collection also including games borrowed from other users.
One more reason to run the Flatpak version then.