DataGrid with AutoCompleteBox crashes Silverlight when scrolling

Question

I have a Silverlight 4 application with a DataGrid. The rows of the datagrid contain two AutoCompleteBoxes.

Whenever the DataGrid shows a scrollbar and the user scrolls the grid, the entire Silverlight plug-in will freeze and crash. When I run it from the debugger, I usually get the following error right before the freeze/crash:

"Error: Unhandled Error in Silverlight Application Code: 4009 Category: ManagedRuntimeError Message: Element is already the child of another element."

I have seen several suggestions on possibly related issues on the silverlight.net forums, like avoiding inline item templates, but I have not yet found a working solution.

What I'm looking for is any information related to this: causes, fixes, work-arounds, methods to further analyse the cause of the problem, anything that could help.

Answer 1

One workaround that I'm currently testing, and that seems to work in my scenario, is to put the DataGrid inside a ScrollViewer. This effectively makes the DataGrid as high as it needs to be and delegates the scrolling to the ScrollViewer, so any DataGrid-scrolling-related problems are hereby avoided.

The only drawback I have found yet (other than that it is a very ugly workaround): the header row of the DataGrid now scrolls out of view, of course, when scrolling down.