Question: is this feature needed at all? The only use I see for it is to take screenshots of a certain resolution, but that's a bit of a weak motivation. I don't see any other reason. If someone wants to play on a smaller window, they can minimize it and choose any size.
In my opinion, if it were to be, it clearly requires a name change. On the other hand, if the goal would be to add an actual resolution setting function in the near future in place of the one that resizes the window, it might be better to keep the wrong name for the time being. Here I would like to point out once again that adding this function would only make sense if it were a multiplier of x2, x3, x4, ... Choosing any resolution other than multiple would blur the game view, so making the function work as is currently visible would be a bad solution.

If you enable "full screen" it will actually change the screen resolution (at least on Windows).

we could instead disable the setting if anything other than "full screen" is used

If you enable "full screen" it will actually change the screen resolution (at least on Windows).

I never used full screen mode and didn't think it actually worked. Man learns all his life :D

we could instead disable the setting if anything other than "full screen" is used

I think that would be appropriate. But the question is, could this resolution change work also for a windowed game? Then choosing the resolution 1/2, 1/3, 1/4 should give a very good effect without blurring for screens with high resolutions.

I think that would be appropriate. But the question is, could this resolution change work also for a windowed game? Then choosing the resolution 1/2, 1/3, 1/4 should give a very good effect without blurring for screens with high resolutions.

there's a gui zoom setting for that

we could instead disable the setting if anything other than "full screen" is used

I like that solution.

Or it could be renamed to "Window size" if it's not full screen? I at least still like to pick a resolution even though I use OpenTTD in a window, rather than dragging the window to an arbitrary size.

This is absolutely standard terminology...

Or it could be renamed to "Window size" if it's not full screen? I at least still like to pick a resolution even though I use OpenTTD in a window, rather than dragging the window to an arbitrary size.

Fair enough, that is enough to leave it in. What to name it really becomes bikeshedding .. what-ever you do, someone will complaint. So I suggest to just leave it as it is ..