[democrite]

The number of steps and required mouse movement to create a highlight I think could be reduced. Attached screen shots of Kindle and Kobo for iOS. I assume B&N and apps for Android work similarly.

The pen icon to create a highlight could be a colored circle with the current highlight color. That specific point, I am undecided as most or all apps I know of quickly create a one-tap highlight from the previously used color. Selecting the icon should be enough to create a highlight with no confirmation; the mouse cursor is already in that location and is quickest. Most of time, I think with print too, people make highlights without notes. As such, adding a note is a separate icon that brings up the dialog when needed. If I want to just make a bunch of highlights, it is quickest.

I might also prefer only 5–6 or so colors, the ones typical of highlighers. Apple Books uses yellow, green, blue, pink, purple, and maybe a nice addition, red underlined. Brighter than current colors I think is better.

One other thing. Any plans for EPUB 3 page numbers? Showing them in the side margin I think you once mention you'd revisit the question after version 4. Many EPUBs now come as such, and it'd be nice.