Source code of standard widgets

Hi there,

I´ve seen this topic and don´t want to issue a new one.

Does anyone know how to implement the code files into a custom widget ? I´m using the selection widget for some items. But I´m not satisfied with 2 points:
1.Size and color for “name”
2.Size and color for selection values

I want to modify this in the code, if possible and use it like a custom widget.

Thank you very much.