As per my understanding when you override system client library (in this case the widget) then only the rendering system kicks off request calls to include system libraries based on categories defined (by default). As you have overrided the system client library you will be using same category and may be added custom category/dependencies. The system will make request based on categories defined and invoke all the libraries which will include default and your custom widget and which ever load last (means closer reference) will serve the feature.
So now even if you have a new project & wants to use the default widget the client library processing will execute same as above. One thing you can try to copy paste the default widget inside your new project and try to define and make a call such a way so that it loads at last (you have to figure it out) with given category but at the same place where it require and initiate the widget load.
# Add some custom category and try to invoke it so that the same can be used by widget
I am sure this is not complete solution and as of now i am also trying to figure it out but will help you to procedd.
All the best.
I was wondering if this would help me use default security Admin UI for Project B and customized Security admin UI for projectA, because ultimately both use the same Security Admin right?
Ultimately any changes to Security Admin, Create Users or Edit Users UI will affect all the projects, this is what i arrived to.Please correct me if i am wrong
That's correct. Its because you have to use same category for each of these widgets and system will invoke and make available on page in order it receives them. Also plz check with day care if there is any break for this.