New PR replaces the custom TabbedPageSet with ttk.Notebook.  On Windows, with default settings, the look is nearly identical, but the selected tab is more obvious.  A method call (note.enable_traversal) will enable navigation between tabs with cntl-tab and cntl-shift-tab.  This will work a bit better with extracted page classes.

On the otherhand, attaching the frame to a notebook instead of the one disables one of the simulated mouse clicks.  I added the remaining part of tkinter.test.support.simulate_click(sp??) to no avail (not surprising since designed for Xwindows.  I also moved the location of the simulated click.  Using ttk.Frame requires the padx, pady to padding change in PR2654.

Please test on linuxes (and mac if possible).  Does the tabset look at least as good?  Does the test run if the #s are removed?