Selecting text upward cancel out the selection

Hi, I found a weird behavior, don’t know if it’s on purpose. when I drag upward to select text, the selection will cancel as soon as the pointor touch the border of prosemirror. Selecting downward won’t behave like this. see this gif:

Which browser are you using?

I’m using Chrome Version 67.0.3396.79 on macOS High Sierra. I experiencd this behavior on both my own project and ProseMirror Demo Page.

I can reproduce this on macOS Chrome, but if I replace the ProseMirror instance with a plain contentEditable div, the selection behavior is exactly the same (inverse selection also resets when exiting the element), so this appears to be default browser behavior and not something ProseMirror is doing.