Calls .config(background=colour)
    Then loops through .winfo_children()
    And if not __widgetIsContainer() calls __setWidgetBg()

.set XXX Bg(colour)
    If METER calls setBg
    If TABBEDFRAME calls setBg
    Else calls __setWidgetBg()
.__widgetIsContainer() - checks the isContainer field
.__setWidgetBg() - the big one!
    Checks widget type, then calls appropriate setters

tabbedFrame rethink: BGs: * Container - only visible at end of tab bar * Tabs - active/inactive * Panes - each one

Therefore: * Make tabs/Panes match colour! * have active/inactive writing colour * container BG

activeforeground activebackground

bg fg

disabledforeground disabledbackground