Played the game at a lower screen resolution (non fullscreen) and attempted to adjust the screen size and it crashed.

Would it be possible to have a resizable resolution rather than custom resolutions?

Hi, you should be able to resize the window to whatever size you want, I did not put any restrictions. Although if you play in too small a window, some of the in-game windows might not be on the screen. See below gif for demonstration.

I am not sure what would cause it to crash though - can you provide steps you use to make it happen? E.g "1. Start the game 2. Go to Options 3. Select 1920x1080...."

Also you can go into Options and resize the UI Scale to make text smaller if you want to play in a smaller window

Yea, i had selected the option to play at a lower resolution in the options screen.  Then i simply went to drag it like you are doing and it crashes.  It just happened again when on starting screen.   Im not sure what else i can tell you other than im doing exactly what you are doing in the clip above.

edit -  Just  checked my windows 10 machine and the dragging works just fine.  My windows 7 box appears to be the only one crashing.

That's interesting, I used a Windows 7 machine to make that gif! 

If there's a certain resolution you are looking for, I could add it to the list of options so you could select it to avoid the crashing problem.

No its fine.  I was just dorking around on my work laptop with it.  it seems to be fine on my dedicated gaming rig.  i guess its just something about my work box that the game doesnt like.