Created attachment 367130 [details]
screenshot

I've noticed that many dialogs, like Sample Points, won't shrink farther than a certain amount. I would expect the dialogs to scroll when smaller than their default size, but the sample points dialog and a few others just won't become smaller. That particular one doesn't even shrink past half the height of my monitor!

Huge usability issue for me (on a monitor with a height of 768), because it means that I can't have certain collections of tabs docked together or else they won't fit the screen. Look at the attached screenshot for an example; the FG/BG color dialog and the Sample Points dialog are both as short as they can be, and I still can't position one on top of the other.

So I would propose a few ways to fix these limitations, to start. Here are the specific dialogs that I had to remove from my normal setup because I noticed that they wouldn't fit with other things:  
Sample points—shrink the vertical space between "B:" and "X:," and once that is exhausted, allow the rest of it to scroll off-screen.  
FG/BG—shrink the massive color wheel/picker/whatever.  
Brush editor—absolutely one of the worst offenders. Just make it scroll when it's shrunk past the current minimum!

Good examples of dialogs that have small minimum sizes include Fonts, Layers, Tool Options, etc.

It's really annoying that these limitations exist. Whether the color wheel gets too small or whether it's ugly to have a scrolling dialog shouldn't be of concern to anyone but the user.

Anyway, a quick fix for many of these dialogs would just be to write the UI code so that once a window gets shrunken past its current minimum, it just scrolls down. Wouldn't really work well for FG/BG, though. For that one, the wheel could be shrunk, or the sliders squished, or something else.