style.layout('My.Horizontal.TScrollbar', [('My.Horizontal.Scrollbar.trough',
    {'children': [('Horizontal.Scrollbar.leftarrow', {'side': 'left',
    'sticky': ''}), ('Horizontal.Scrollbar.rightarrow', {'side': 'right',
    'sticky': ''}), ('Horizontal.Scrollbar.thumb', {'unit': '1', 'children':
    [('Horizontal.Scrollbar.grip', {'sticky': ''})], 'sticky': 'nswe'})],
    'sticky': 'we'})])
style.configure('My.Horizontal.TScrollbar', *style.configure(
    'Horizontal.TScrollbar'))
style.configure('My.Horizontal.TScrollbar', troughcolor='red')
hs = Scrollbar(app, orient='horizontal', style='My.Horizontal.TScrollbar')
hs.place(x=5, y=5, width=150)
hs.set(0.2, 0.3)
app.mainloop()
if __name__ == '__main__':
    main()
Changing the appearance of a Scrollbar in tkinter (using ttk styles)