public static int GetInternalLabelWidth(this PropertyGrid propertyGrid)
{
//System.Windows.Forms.PropertyGridInternal.PropertyGridView
object gridView = GetPropertyGridView(propertyGrid);
//protected int InternalLabelWidth
PropertyInfo propInfo = gridView.GetType().GetProperty("InternalLabelWidth", BindingFlags.NonPublic | BindingFlags.Instance);
return (int)propInfo.GetValue(gridView, new object[] {});
}