class Navbar(tk.Frame): ...
class Toolbar(tk.Frame): ...
class Statusbar(tk.Frame): ...
class Main(tk.Frame): ...
class MainApplication(tk.Frame):
def __init__(self, parent, *args, **kwargs):
tk.Frame.__init__(self, parent, *args, **kwargs)
self.statusbar = Statusbar(self, ...)
self.toolbar = Toolbar(self, ...)
self.navbar = Navbar(self, ...)
self.main = Main(self, ...)
self.statusbar.pack(side="bottom", fill="x")
self.toolbar.pack(side="top", fill="x")
self.navbar.pack(side="left", fill="y")
self.main.pack(side="right", fill="both", expand=True)