>How do I subclass a MM form or MM control?

The same way you would sub-class the base .NET controls. I typically have a project that's included in all my apps that contains most of these sub-classes. Things like Forms can be sub-classed visually ... add a Form to your project (right-click, add new Item, choose a Form), then simply go to the code and change:

public partial class MyForm : System.Windows.Forms.Form

to

public partial class MyForm : MMForm

(I don't use MM, so I don't know what the proper name of the form is).

Other things, like TextBoxes, Buttons, etc., can't be sub-classed visually. So basically, you'll want one big class library (one file) that contains your sub-classed UI controls. Something like this:

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace MyCompany.MyFramework.WinUI.MyClasses
{
	public class MyComboBox : MMComboBox
	{
		// code here
	}

	public class MyTextBox : MMTextBox
	{
		// code here
	}

	public class MyButton : MMButton
	{
		// code here
	}
}

That's it.

~~Bonnie