Won't Fix: Such behavior can be observed only when there are elements with greater width than the default one of the RadGridView's FilteringControl. To resolve this, create a Style which targets the FilteringControl and sets the MinWidth property to zero and the Width property to the MinWidth's default value. Also, check the following article for a further reference - https://docs.telerik.com/devtools/wpf/knowledge-base/kb-gridview-filteringcontrol-changes-its-width-while-scrolling.