pack://application:,,,/ResourceFile.xaml Never Works

Question

I have never been able to get this format of reference a Resource Dictionary to work. What am I missing.

Scenario:

Creating and assembly with some usercontrols i

Answer 1

try:

pack://application:,,,/YOURNAMESPACEHERE/ColorThemes.xaml

E.g.

pack://application:,,,/Themes/ColorThemes.xaml