How to add XML comments to a Win Forms class?

I am trying to document my code using XML comments. I have a Windows Forms class where I am attempting the following

/// <summary>
/// A special window class
/// </summary>
public partial class SomeSpecialWindow : Window {...}

My comments are not showing in the Inetlisense for my class. This is because in the case of partial classes, only the comments given for one of the partial definitions are picked up by the IDE. Obviously the comments being picked up by the IDE are not the ones I am writing, but I cannot find the other half of the partial class so I can remove the comments so mine will show up instead.