After the upgrade to 6.2 the NetXMS client on Windows is VERY slow. Every time a gridview is shown, it uses a lot of time to refresh the grid and adjust the column width - and it does that very often because of automatic refresh cycle and makes the client very slow.
Fortunately the issue is not the same on the web-client.
It's a know issue, we are working on that right now. Should be improved in next patch release.