I put a message on the forums during the beta about this issue. But I'm not 100% sure the CMs (though rather helpful) understood the issue. So this time I decided to use 2 screenshots of Diablo 3 and another game to illustrate this issue I believe needs fixing.
A screenshot of the Torchlight options area accessed via the title screen. Notice how I am in windowed mode. The red box I put on the screen shot is there to illustrate the fact I can use drop down resolution menu (while in windowed mode) to change the resolution of the game. Basically changing the size of the game window.
This is pretty much how almost every game I I have played with a window mode works. All good.
A screenshot of the Diablo 3 retail options area accessed via the title screen. Notice how the red box is around the resolution option. In fullscreen mode that resolution option is active and you can use it. But in windowed mode as you can see the option is greyed out and unusable.
And this is my issue. I strongly believe this option should be usable while in windowed mode. Yes I understand you can manually resize the window by dragging the corners. But I wanted an exact resolution like you can get in fullscreen. Dragging the corner of the window would not get me this easily so I had to find the preferences file (OS X) and edit the window size to get the one of the same resolution options that full screen mode has to offer.
This is a screenshot of the Diablo 3 preferences file on OS X. Notice the red box I added, that's where you can edit the windowed mode resolution to get an exact figure. But you know this already.
I found this preferences file at this location
~/Library/Application Support/Blizzard/Diablo III/D3Prefs.txt
TDLR (A short summary of the above.)
I want to play Diablo 2 in 1600x900 resolution exactly. In full screen mode I can do this. But in windowed mode I can't do this without editing the Diablo 3 preferences file. In no other Non-Blizzard game I have played is the customer forced to do this. They can just change the windowed screen resolution to whatever pre-set resolutionsthey want, just the same as in full screen.
I believe not being able to change the windowed resolution ingame to an exact amount (like you can do in full screen) is a basic feature that should be in the game. I am a little disappointed it is not. Diablo 3 looks amazing in almost every other way. But this is bugging me cause I like windowed mode and don't like being forced to go edit the preferences file every time I want to change my windowed mode resolution (to exact values) to optimise my ingame fps.
This needs a fix.