On Sun, Aug 15 2021, Lars Ingebrigtsen wrote:

> Do you get focus-in events when you do the changing between pages in the
> way you describe?

No. Neither focus-in nor focus-out events...

Now I've checked the events with "xev -id 0x140013e":

ConfigureNotify event, serial 18, synthetic YES, window 0x140013e,
    event 0x140013e, window 0x140013e, (3843,2334), width 3389, height 1963,
    border_width 0, above 0xa0016e, override NO

-- 
           Peter