Remove black background behind the dialog list and maintain the edges's shape once the color changed.

Removing lack background when showing a dialog list. By default, there is always a black thing behind the dialog list's appearance. 

Mantaining the shape of the dialog list after changing its color. Currently the edges lose its rounded shape once you change the color. This will make the presentation of the dialog list clunky and stiff.

I'm running on Android 10, and it seems like it's a bug rather than a feature, but i would love to see the dialog gets improved in the near future. Thankyou