change UI to match with ubuntu standard

Several ideas from the mockup:
 1) Match ubuntu theme in the header
 2) Use search combobox instead of combobox + button combination

Apart from the installer and the Ubuntu One dialog, I haven't seen this kind of UI anywhere else.
I can't say that it is a "Ubuntu standard". Am I missing something?
The problem is that gtk assistant does not let you use different colors.

It is not standard, but it will look better, and also ubuntu tweak will use it, and maybe my rss reader :-D

We have to think about consistency. If the location add/edit dialog uses the black header, then the preferences dialog should look like that too. All the system indicators use standard preferences dialogs. I think that we should wait until they actually change (or plan to change) to a new standard. If we change now we'll be completely out of place.

Maybe something should be posted on Ayatana asking when these new "standards" will be implemented.

If this is implemented, might I suggest that you look into making the look into a dedicated .rc file in the Ambiance/Radiance theme folders so that the window won't look out of place when not using those themes?