Hello Cees Van
Just to clear things out, Data Grid Web work with REST endpoints, and after deleting the registers a new fetch is done. If you want to do some debug the maybe you can start by the method bellow, this is the start to send removed rows.
GridOS.SelectionFeature.sendJsonRemovedElements
But I think I didn't get your error, could you please share a sample with us, or maybe an animated gif showing the errors happening?
Thanks
Ricardo Valim