So I know this is old but i just came across this in WPF.
where the Visual Class (the class that creates visual items in wpf) is in the System.Windows.Media namespace

the adorner class lives in the System.Windows.Document namespace but inherits from Classes in the System.WIndows.Media namespace.

so im a newbie but Im seeing the microsoft team do this all the time.

Namespaces seem to be just away to organize files not to prototype class inheritance.