I often use a Wacom graphics tablet for general computer use for ergonomic reasons but I've noticed the Steam client's new and (mostly) improved video system does not work at all with my Wacom pen because due to the inherent slight imprecision of pen interaction compared to a mouse you're always slightly moving a few pixels when clicking, and so the software thinks I'm trying to click & drag when I'm just trying to left-click (by putting the pen down on the tablet). As a result it is impossible to for example press pause or fullscreen on a video on Steam unless I switch to my mouse.

I realize this is a niche issue as most will not be using tablet pens to interact with Steam, but it would be great if you could slightly increase the mouse drag threshold so that a click with a pen registers as a click. Perhaps you could make it an exposed setting that users can customize, though I doubt having a slightly wider threshold for click & drag would interfere with mouse input here.