So, i have a DataGrid using the latest SDK (4.5.1) with 500 rows of data and 14 columns. I'm not using any custom ItemRenderers at all; the data is just string and number properties of each data object in an ArrayCollection. When I try to scroll vertically, either by clicking on the scrollbar handle and dragging or by using the arrow buttons, the performance degrades so badly that the application appears to freeze up completely for a few seconds. (I'm on OS X, and I see the spinning beachball icon.) The app then remains so unresponsive as to be pretty much unusable.
The exception to this is when, rather than launching the app as a debug configuration, I just refresh the page so the swf can run without the debugger attached. Detached from the debugger, the performance is great, every time. This is, BTW, using the very latest build of Flash Builder 4.5 Pro; I just installed it last week.
I've tried eliminating various possible causes, and haven't had any luck. I made the data non-bindable, removed all the custom skins and css styling, and even removed event listeners from the DataGrid; none if it seems to make a difference.
Has anyone else noticed this issue? Is there a workaround? If the debugger is to blame (which seems likely), is there some setting that I can turn on or off that will help?
Few days ago I've had the same issue.
Windows 2008 server (i'm working on remote desktop)
Flex SDK 4.5.1
Firefox 8.0 (on Explorer was ok).
Flashplayer version 10.2.153.1
It happened to me only that day (run without debugger, restart application didn't work), but it seems that when I log out from Windows and log in again the problem disappeared.