RE:contenido de un textbox
Tendrías que utilizar los eventos Mouse Down y Mouse Up
para colorear el Background o restaurarlo.
Private Sub Text1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
Text1.BackColor = vbRed
End Sub
Private Sub Text1_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
Text1.BackColor = vbWhite
End Sub
También, si querés simular a Delphi, podés utilizar el evento LostFocus para restaurarlo