Stick_to_end. Bug Report or misunderstanding

I have no problem with items with different heights mentioned in #1376, but I have some doubts about stick_to_end as mentioned in #1376.

Concerning the stick_to_end, I found that it is some kind of stick_to_begin. It is not stick to the bottom.
As shown in the demo "Scrolling" -> "stick_to_end", when a new row is added, "stick_to_bottom"("end") should ensure the last few rows to be shown, rather than the beginning rows to be shown.

If stick_to_end indeed means stick_to_beginning, then we need stick_to_bottom, so when new rows appended to the end, those new rows should appear at the bottom.

Any idea about this?

Start with the "Scrolling" demo's "stick_to_end" example and compare its behavior with the expectations described in #1376. Reproduce the case by appending rows, determine whether the current behavior is intended or incorrect, and document or test that the newest rows remain visible at the bottom when sticking to the end.

Written by the indexing model from the issue text.