MPC-HC + madVR - HDR pass through only works when MPC-HC is windowed.

I am playing a 4k HDR bluray with MPC-HC + madVR on a "fake" HDR screen (8+2 bits). If MPC-HC is windowed, I see the HDR. If I make MPC-HC fullscreen, the colors dull. If MPC-HC is not in focus or I bring up the seekbar, the colors go back to HDR. Why is this? I installed MPC-HC/madVR using K-Lite code pack. Everything is default settings.
I am on Windows 10. Full screen is "regular" fullscreen, not full screen exclusive.
iGPU: HD 630
dGPU: NVIDIA 1050 Ti Max Q
both drivers are up to date

Most likely a driver issue.

In the Windows 10 display settings you can configure which GPU is used by MPC-HC. You could test if that makes any difference.

Admin wrote:Most likely a driver issue.

In the Windows 10 display settings you can configure which GPU is used by MPC-HC. You could test if that makes any difference.

I am on a laptop with integrated and dedicated graphics. Using dedicated graphics prevents any HDR from showing.

One option would be to manually enable HDR in the Windows display settings. Maybe then it will stay in HDR mode.

Another option is to disable HDR passthrough and let madVR do the tonemapping.
madvr settings > devices > hdr > tone map HDR using pixel shaders

If performance is not good enough with madVR, then you could try "MPC Video Renderer" instead. That has better performance, but also a bit lower quality.