Modified TextBox for forms generating SQL statements
There's not much to review here really. I'd be more interested in reviewing the code that's actually doing the work, but here goes. 


Lose the Systems Hungarian notation. The IDE/Code tells me what the data type is. That is if you...
Declare the data types of the properties
Use auto properties. There's way too much code here for how simple this is. 




Public Class ModifiedTextBox
    Inherits System.Windows.Forms.TextBox

    Property ID() As Integer
    Property TextModified() As Boolean
    Property SqlText() As String

    Property DefaultText() As String
        Set(strDefaultText)
            _strDefaultText = strDefaultText
            Me.Text = _strDefaultText
        End Set
        Get
            Return _strDefaultText
        End Get
    End Property

End Class