For a monitor with internal LUTs (like the Benq), the Windows monitor profile is merely a description of the colour space of the monitor. The profile tells the displaying program how to colour-manage the image to get the right colours on the monitor. If you change the monitor profile in Control Panel, nothing changes unless the program notices the change of profile and re-renders the image on the screen. Remember, it's the program, not Windows, that does colour-management.
Most programs check the profile only when they first run, which means you need to exit the program and restart for them to notice a change of profile. Photoshop does check, but not continuously. Sometimes, clicking the image is enough for it to check and re-render, sometimes I find I need to minimise and restore the PS window before it tries to re-render and notices the change of profile.
Going on from what I said before, to change the monitor colour space and get a program to notice and render correctly, you need to do three things:
- Change the monitor color space (in the case of Benq with the puck or front panel buttons)
- Change the Windows monitor profile to reflect the new monitor colour space
- Make the prgram re-render with the new profile, which means for most prgrams one must exit and restart, or for PS force it to re-render the on-screen image.
For some monitors (e.g. Eizo, not sure who else) there is a utility to do both (1) and (2), but (3) depends on the program that's displaying the image.
For this reason, I rarely change the monitor colour space. I leave my two monitors (one Benq, one Eizo) calibrated to their native (widest) colour space, and if I want to see what something looks like in sRGB, say, I use soft proofing. One click in LR or PS instead of a lot of faffing around.