Option to select dark or misc background for Traffic Graphs when a dark theme is selected.
When a dark theme is selected, the large "blob" of white color in
the Traffic Graphs widget feels inapropriate when majority of the
dashboard is in dark color and it would be nice to have the option
to select a darker theme for Traffic Graphs.
Either add an option to "Light/Dark" or "User selected colour"
and/or "Use theme default".