Page Up / Page Down shortcut skips pages
Testing with the nightly flatpak version, pressing PgUp
/ PgDown
on the keyboard, even after clicking/selecting something in the main contents view (to be sure the sidebar thumbnails are not the thing that have focus), PgUp/Down skips pages (especially the ones in the "middle" of the sidebar) instead of always going up/down 1 page at a time.
Demonstration video: