to see the effects generated by these two scriptssettingstry out few changes on your computer most widgets can be given custom appearance in the same wayand we'll see such options used repeatedly in this text we'll also meet operational configurationssuch as focus (for focusing inputand others in factwidgets can have dozens of optionsmost have reasonable defaults that produce native look-and-feel on each windowing platformand this is one reason for tkinter' simplicity but tkinter lets you build more custom displays when you want to for more on ways to apply configuration options to provide common look-and-feel for your widgetsrefer back to "customizing widgets with classeson page especially its themedbutton examples now that you know more about configurationits examplessource code should more readily show how configurations applied in widget subclasses are automatically inherited by all instances and subclasses the new ttk extension described in also provides additional ways to configure widgets with its notion of themessee the preceding for more details and resources on ttk top-level windows tkinter guis always have an application root windowwhether you get it by default or create it explicitly by calling the tk object constructor this main root window is the one that opens when your program runsand it is where you generally pack your most important and long-lived widgets in additiontkinter scripts can create any number of independent windowsgenerated and popped up on demandby creating toplevel widget objects each toplevel object created produces new window on the display and automatically adds it to the program' gui event-loop processing stream (you don' need to call the mainloop method of new windows to activate themexample - builds root and two pop-up windows top-level windows