Thank you for writing.
When you create a theme with Theme Builder (aka Visual Style Builder), it is output in an .xml file. When you load this xml file with RadThemeManager, by default the theme is not set to any control, but you can select the theme by choosing it's name from the ThemeName
property in the button's smart tag. This way only this button will have the theme. The only way the theme can be applied to every button is when you set the ThemeResolutionService.ApplicationThemeName
property or if you call ThemeResolutionService.ApplyThemeToControlTree(Control parent, string themeName)
by passing your control container as the first argument and the your theme name as the second argument.
I have attached a sample application with a theme added as a resource, like you described. Theme is applied to only one of the buttons.
Please have a look at the project and write back if you need further assistance.
the Telerik team