There are 3 Track Bars on the Form. The first Track Bar is stands for Red, second for Green and third for Blue, depends on the position of indicator the background color of label is display on Mouse Move in VB.NET.

Public Class Form1
    Private Sub TrackBarBlue_Scroll(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TrackBarBlue.Scroll, TrackBarRed.Scroll, TrackBarGreen.Scroll
        Me.BackColor = Color.FromArgb(TrackBarRed.Value, TrackBarGreen.Value, TrackBarBlue.Value)
    End Sub
End Class