Scrolling with built-in trackpad of MacBook Pro on macOS very unsmooth

[Kal Sze]

Calibre 5.9
MacBook Pro (Retina, 15-inch, Late 2013) - MacBookPro11,3
macOS Mojave 10.14.6

1. Open an epub for reading;
2. Set "Flow mode", not "Paged mode";
3. Scroll the book using the built-in trackpad;
4. Notice how unsmooth the scrolling is. The viewer would stutter every few lines;
5. Press Ctrl-L to open the Lookup drawer;
6. Select a word in the book to trigger lookup;
7. Scroll the dictionary page opened in the Lookup drawer using the built-in trackpad and notice it's buttery smooth;
8. Use the scroll wheel of a regular mouse to scroll the book page area and notice it behaves as normal and does not stutter.

i.e. the book page area's scrolling stutters only when using the built-in trackpad.

I also use Calibre 5.9 on a Dell laptop running Kubuntu 20.04.1, and there's no such stuttering when scrolling with the built-in trackpad there.

[Kovid Goyal (kovid)]

Fixed in branch master. The fix will be in the next release. calibre is usually released every alternate Friday.

 status fixreleased

[Kal Sze (ksze)]

The fix works like a charm! Thanks!