In the fute, please make one thread consisting of all your suggestions, not a thread per. Secondly, as far you not knowing if a feature suggestion was made, that's why god (Khaled) gave us
Search Now, as far as your suggestions:
1. Download manager in one window
Not a bad idea, as it would take some buttons off the switchbar and make it easier to follow progress, sources, etc.
2. Menu editor
You have one, its in the popups section. Editing anything further is pointless. If you need subcategroies, make them in your main menu..
[ File ][ Options ][ View ][ ... ]
could become
MyMenu
.File
.Options
.View
As for nicklist coloring, Ehh, I could go either way. It could be added, and used by those whom want to, and ignored by those who don't, so I don't see any problem with it. But just fyi, this was suggested previously.
