How to apply a custom style to an existing control while maintaining default styling

[Roypy]

I can't seem to understand how to apply a custom style to the ui:Button. I've tried this
<Style TargetType="{x:Type ui:Button}" BasedOn="{StaticResource DefaultUiButtonStyle}"/> but that gives me an error

SeverityCode Description Project File Line Suppression State
Error XDG-0001 The resource "DefaultUiButtonStyle" could not be resolved.	

Same error as above
<Style x:Key="buttonStyle" TargetType="ui:Button" BasedOn="{StaticResource DefaultUiButtonStyle}"/>

If anyone knows what style to reference or how to exactly customize the style while still basing off the default it would be helpful.

[Roypy]

Solved my own issue, started a new project and re-added WPFUI worked flawlessly after. I know it's not really a good answer, but I guess something was messed up in my other project.