DataGrid scroll positions resetting with dynamic dataprovider

Question

Hi - I have a DataGrid that is backed by an ArrayCollection
that is fairly dynamic. Before doing my updates, i disable
autoupdating, and though my size is typically fixed at 100 items,
sometimes those items will be replaced. My problem is that a user
who has scrolled down the visible grid, will lose their scroll
position when i replace items. If i'm just doing updates on the
existing objects, it's fine, but the replace is causing the scrolls
(both horizontal and vertical) to reset. I've tried to isolate
where this is happening (whether set verticalScrollPosition or on
the bookmark) and i can't quite find it.
Anyone know how i can prevent this behavior? I've tried
capturing the scoll position before i begin my updates, and then
setting it back when finished, but it doesn't work.
Thanks.
./paul

Answer 1

Actually, I spoke too soon. I had a number of things I was
trying. And when i tried to clean up the other things that I
believed were extraneous (including an override of
makeColumnsAndRows), the vertical scroll resetting stopped working.
I've spent about 90 minutes trying to get back to where I was (wish
the builder was in IntelliJ!).
When it was working, I also tried to add horizontal scroll
capturing, and that didn't seem work either. I have 34 columns, the
first one is locked. When I captured my position, I saw it was 11.
Then i performed the update, and callLater my resetScroll position.
The first column i saw after the locked column is correct. However,
the scroll bar itself is fully left. On the next update I captured
a horizontal scroll of zero.
./paul