The same entries are coming up while scrolling up with large store.

[keijim2]

It looks like an issue of VScroller.
When store has many items, the same entries are coming up while scrolling up from bottom to top. Items in top area does not appear gradually. The problem does not occur when you scroll down.

I can see the same phenomenon at the test page of gridx. Here is a reproducible steps.

1. Go to https://oria.github.io/gridx/demos/test_grid.html
2. Scroll down to the bottom of the entries (100th item is displayed)
3. Scroll up by mouse wheel (or keyboard)
   -> Items in 70s or 80s are displayed repeatedly. And items in 40s or less are not displayed until you reach to the top

Expected behavior:
Based on the scroll position, displayed items are updated gradually.

Reproducible environment:
gridx: 1.3.8
Chrome on Widows 10