Hi Christian Surieux,
This sounds like a problem with the way the control is databound. One possible option in this case would be to use a template column and have one control for normal mode, and one for edit mode (item and edititem templates). This would offer you enough flexibility to achieve the task at hand. Also, you can have the combo to Load on demand, which would allow you to feed data to it in the ItemsRequested event handler.
I hope these suggestions help.
the Telerik team
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