Is it possible to go above 50fps?

[CSGamma]

Hi, I’m wondering if it’s possible for an overlay window to display at more than 50fps (eg 60fps, 120fps, etc)? If not, could this be achieved by editing part of the script or code? Thank you!

[elvissteinjr]

Depending on what overlay type it is, there are different factors to it.

If you are indeed talking about a window overlay, then its maximum refresh rate is tied to the display refresh rate of the desktop it's on.
If it's about desktop overlays as well, this also applies, but with the exception that exclusive fullscreen application are able to go past it under the right conditions. The User Guide describes those.
Browser overlays probably aren't of concern here, but there's a separate maximum frame rate setting for them.

If you're just talking about the update limiter settings, then yes, the fps slider there maxes out at 50 fps. The reason for it being that these are just frame-time presets for the limiter and above 50 fps it becomes a bit inaccurate.
A simple fps cut-off limiter would not work well with the intermixed cursor updates from the capture API.
If you want to limit above that you can use the frame-time setting for the update limiter and use a smaller number there to get roughly somewhere.
And of course if it's unticked, it won't do any limiting.

That being said, by default on a bog-standard system with a 60 Hz display there should be nothing stopping you from getting 60 fps captures. You can enable "[x] Show FPS in Floating UI" in the settings to double-check what you're getting.
Generally, if you have a mouse with a high polling rate, you usually see the fps exceed your display's refresh rate for desktop overlays as the cursor is updated separately and more frequently.

[CSGamma]

Ah I see, I misunderstood the role of the update limiter/overrider. Thanks so much for your detailed explanation, very helpful!

Just a quick one if you don’t mind: is there any way to get Desktop+ to recognise and track the Logitech MX Ink (that 3rd party stylus made for the Meta Quest)? I know SteamVR only picks up the default Quest 3 controllers, so I was wondering if it might be possible either through a bit of code or some workaround, or if it’s likely a bit too complex to implement? Thanks.

[elvissteinjr]

It seems that at the lowest level, they do provide OpenXR support. So that at least means it's not tied to a bigger engine via plugin only.

With that being said, Desktop+ is OpenVR-only. Running an OpenXR session to pass input data along seems within the realm of possibility, however.
That is, if the OpenXR input device appears as such on the PC in the first place. I'm not 100% sure about that.
Their FAQ also says it'd appear as a Legacy Touch Controller for unsupported apps.
Again I have no clue what happens on PC there. Probably also depends on what you use to connect the HMD to the PC.

And I guess it depends what you want from the pen. As far as integration goes, if you can get the tracked device data, using it as a overlay origin is simple, but probably not what you're after.
Overlay interaction seems likely. But Desktop+ only does classic laser pointing, no on-touch input. Wouldn't be terribly hard to add though, to be fair.
Pressure-sensitive input would need to be added if desired. Pen input simulation is already there at fixed pressure, so that's viable too if you can get the data from the device.

Well, that's at least what I can come up with here. I can't really assist with any of this due to lack of hardware and OpenXR experience.
And if I'm 100% honest, I'm not sure if I'd accept such integration into the main repo if that's a goal. It just seems very niche and not something I could maintain/test support for.
Not that you need my approval to get things running on your end of course.

Still, I hope that helps somewhat.