Welcome to TVPaint Community forums !

Good to see TV paint at Siggraph this year.

My laptop monitor is 1920 x 1080. I want to keep my layers window there. My 'secondary' monitor is 2560 x 1440, I want to work there. My attempts to set this up result in the interface restricting itself to 1080 pixels high. Looking for a way around that, if there is one.

Hi, nice to see you back.
Unfortunately as of now you cannot undock a subwindow outside of the main tvpaint window. The behaviour you are experiencing is to be expected if you are on Microsoft Windows and i'm afraid there is no way around.
I just tried on a dual monitor setup, both 2560x1440 and it seems comfortable to work with, the issue is due to the difference in size beetween your two monitors.