Figured it out. You have to use a DescriptionAttribute and a CategoryAttribute.

Here's an example:

Code:
Imports System.ComponentModel

Public Class MyUserControl

    Inherits System.Windows.Forms.UserControl

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    <Description("The current date value for this control"), Category("Behavior")> _
    Public Property Value() As Date
        Get
            Return mdteValue
        End Get
        Set(ByVal pdteValue As Date)
            mdteValue = pdteValue
        End Set
    End Property

End Class