It should have similar behavior to the one in RadGridView https://docs.telerik.com/devtools/wpf/controls/radgridview/columns/column-groups
Thanks,
The FilterColumn method does not position the filtering popup on the passed column index when it is opened.
A workaround to this behavior would be to manually position the filtering popup using the following approach:
this.virtualGrid.FilterColumn(2);
var virtualizingCanvasBase = this.virtualGrid.ChildrenOfType<VirtualizingCanvasBase>().FirstOrDefault();
var columnsRenderInfoInfo = virtualizingCanvasBase.GetType().GetProperty("ColumnsRenderInfo", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
var columnsRenderInfo = columnsRenderInfoInfo.GetValue(virtualizingCanvasBase);
var offsetMethodInfo = columnsRenderInfo.GetType().GetMethod("OffsetFromIndex");
var filteringPopupPropertyInfo = this.virtualGrid.GetType().GetProperty("FilteringPopup", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
Popup filteringPopup = (Popup)filteringPopupPropertyInfo.GetValue(this.virtualGrid);
filteringPopup.HorizontalOffset = (double)offsetMethodInfo.Invoke(columnsRenderInfo, new object[1] { 2 });
The FilterColumn method should be called, in order for the filtering Popup to be created.