Overall the new collection editor works fairly well. But things get screwy when you have more than 40 items. You'll see a "Load More Items" button. Which mostly works. I do notice some duplication. Item #41 is identical to item #40. Probably a minor array index error in the code. But if I then try to reorder items via drag and drop things go haywire. Probably related to that index problem. I end up seeing apparent clones of the item I'm dragging. And eventually the page goes blank with only the header visible. I have to refresh the browser. Thankfully the clones such seen during manual ordering don't appear in the actual publicly visible page.
Technical note. As mentioned, this bug probably is a consequence of an array indexing issue. Let's say you enumerate the items on the first page as 1 - 40. But then on the second page you enumerate as 40 - 79. You would see the duplicate of item 40 as though it were item 41. And using a 1-based index with 0-based algorithms could cause all the cloning and screwy sorting behaviors. And attempting to move an item past the last array index could cause a runtime error that results in the page getting cleared. If I am right about this being the source of this bug then it should be easy to fix.
