Steps to reproduce: 1. Drag a grid on the form 2. Drag one or more controls over the grid - at this point in the Document Outline you can see the dragged control is a child of the grid 3. Open the Property Builder of the grid and close it - at this point the dragged control disappears Workaround: 1. Open the Designer.cs file, and locate the line, where the control is added to the grid e.g. this.radGridView2.Controls.Add(this.radButton4); and change it to: this.Controls.Add(this.radButton4); If need be, set the Location property of the control at design time, to position it at the desired place. 2. Alternatively, you can place the control outside the grid bounds and after selecting it, use the arrow keys to position is over the grid. This will not make it its child, hence the issue will not appear.