@thor @solohan83
Ebook readers have 2 distinct ways of refreshing the image.

The normal, full refresh, first pushes a negative of the current drawn image, then it pushes the new image. This is quite slow.

The alternate way is a fast refresh, that lacks that negative phase. This allows for fast text scroll, but comes with the downside of a distinct ghosting effect. It's usually not noticeable for text (especially for modern e-ink displays), but it can be very noticeable for GUI elements. Which is why you usually get normal refreshes for GUI stuff, which increases the lag you feel.