Expanded Hover (1 Viewer)

 If you are looking for a solution that is self contained within
 control's MouseMove event. You could experiment with sample code 
given below:

' Code in form's module
'==============================
' Declarations section
Private gX As Single, gY As Single
'---------------------------------------------

Private Sub CmdTest_MouseMove( _
                    Button As Integer, _
                    Shift As Integer, _
                    X As Single, Y As Single)

    With Me.CmdTest
        Me.CmdTest.Caption = "Test (MM)"

        If gX <> 0 Then
            If (X > (0.9 * .Width) And X > gX) _
                        Or (X < (0.1 * .Width) And _
                        X < gX) Then
                Me.CmdTest.Caption = "Test"
            End If
        End If

        If gY <> 0 Then
            If (Y > (0.9 * .Height) And Y > gY) _
                        Or (Y < (0.1 * .Height) And _
                        Y < gY) Then
                Me.CmdTest.Caption = "Test"
            End If
        End If
    End With

    gX = X
    gY = Y
End Sub
'==============================

    Normal caption of command button named CmdTest is "Test". 
When mouse pointer is brought over it, the caption changes to "Test 
(MM)". As & when the mouse pointer moves away from the control,
 the caption reverts back to normal, i.e. "Test".

    Note:
    (a) MouseMove event fires in rapid-fire style. Values for X and Y 
returned by this event have a range from 0 upto the width and height 
(in twips) of the control in question.

    (b) The multiplying factors of 0.9 and 0.1 used in the sample code 
could perhaps be fine tuned further (say 0.95 and 0.05) so as to 
narrow down the twilight zone. However a coarser setting as adopted
 above, is found conducive to more consistent behavior. 
This is because a deliberately wild mouse sweep by the user can result
in X or Y value getting truncated short of the potential maximum, even 
though the mouse pointer has moved out. [[COLOR="Silver"]from ADT[/COLOR]]