[ToolboxBitmap(typeof(NumericTextBox))] public class NumericTextBox : TextBox {I've also used:
[ToolboxBitmap(Typeof(NumericTextBox),"EGBClases.NumericTextBox.bmp")] public class NumericTextBox : TextBox {And even tried passing the disk path to the file as in:
[ToolboxBitmap(@"C:\Net Proyectos\NetSolucion\EGBClases\Imagenes\NumericTextBox.bmp")] public class NumericTextBox : TextBox {But none of them work!