apply/preview from subdialogs

[hawk gagarin is]

Hi.

I'd like to throw a UI issue out there for you all to think about.

I'll use the gnome-terminal Preferences dialog as an example. With
the dialog open on the Colors tab, one can select a colour scheme
from the Fore/Background Colour menu and then click Apply to see the
effect of the change. This is good.

But when you have selected "Custom colors" and proceed to choose the
foreground- or background colours, the apply functionality is not as
readily available. You have to close the colour picker for the
Preferences dialog to register the change, update the colour box for
the colour you just changed, and enable the apply button, allowing
you to finally click it and see the effect of your change. Then,
perhaps, you realise the background colour you selected is a little
too bright, and you have to click the Background color box again,
lower the value, close the colour picker, and click apply. Repeat
until happy. This is not nearly as good.

The simplest fix would probably be to have every change made in the
colour picker feed down to the Preferences dialog as soon as it
is made, rather than to just do that when the colour picker is
closed. This puts you one click of the apply button away from
seeing the effect of your changes at any time. This also makes it
easy to add an auto-apply or preview toggle to the Preferences
dialog without touching the colour picker code (a feature I'd
welcome). Similar changes would have to be made to any dialog that
calls a font or icon selection dialog (perha. 

For those who didn't know (I'd forgotten, myself), you can assign
colours to some things in gnome (the terminal for instance) by
dragging a colour from any gnome colour source (the rectangular box
beneath the colour wheel in the colour picker for instance) onto
them. The terminal assigns a colour dropped on an empty character
cell to the background and a colour dropped on a character to the
foreground. 

This is pretty cool, but doesn't solve the apply problem
in general (you can't change gnome-terminal's font that way, for
instance) and suffers from a few problems of its own. The big one
being that it's not obvious that it can be done. You have to read
the help or see the startup hint (I assume there is one) to find out
about it.