I upgraded to beta 4 from 3 yesterday, as per previous upgrades everything went smoothly. However, i noticed a number of issues with the grids. I have grids with expanded columns, which nest another grid (btw this should be an inbuilt feature). The expand buttons disappear on expansion, so i cannot see the 'minus' icon.
If i have several rows and i select a row before an expanded item, it works fine. but if i select an item after the expanded row, it selects the one above it. So if i have 5 expanded items above the item i select, the row 5 items before the one i select is selected.
Also i notices that the performance was terrible, it almost seems like the code has regressed. I understand that the appearance pattern was applied to the grids, but they didn't look as sharp.
As of now i reverted back to Beta 3 but it doesn't inspire confidence.