How to apply custom 4x4 shade to a brush when 'painting?'

[prahou]

When in the 'paint' mode inside any window, holding mouse 3 and selecting SetShade provides a menu with 3 shades and a fourth option 4x4 shade, which opens a window for designing custom shades.

But how does one apply the custom shade as the current brush shade?

Thank you.

[masinter]

Read the code...
It's all there

[prahou]

You have to close the custom shade window first. How about that!