Color based widgets enhancements / introduction

Please review color widgets.
Hum i what is the beahvior when i enter #FFF ?  -> #FFF000? #F0F0F0?
or #F5FF? -> #F5FF00? #F5F0F0?
I think alpha is the only pair not required. but all pair must be complete #FF0000 and sometimes #FF0000A0