How do I update the screen -without clicking out to refresh?

[Cmack]

I have a code to deactivate a command button on sheet 2 when cell A1 is being used.
I have to click on sheet 2 then back to sheet 1 then back to sheet 2 to disable/enable command button (to activate it)
Is there a way to update the commandbutton instantly? (execute the program)

Private Sub Worksheet_Activate()
Dim CV As Boolean
If Worksheets("Sheet1").Range("A1").Value = "" Then CV = False
If CV = False Then Worksheets("Sheet2").CommandButton1.Enabled = False
If Worksheets("Sheet1").Range("A1").Value > 0 Then CV = True
If CV = True Then Worksheets("Sheet2").CommandButton1.Enabled = True
End sub

 

[Cmack]

I have tried
Application.ScreenUpdating = True
ActiveSheet.Calculate
Application.EnableEvents = True
Application.WindowState = Application.WindowState
With limited success- Perhaps these code fragments are in the wrong place
Any help appreciated

 

[Cmack]

I worked it out, for those that need it - use the sheet change command

Private Sub Worksheet_Change(ByVal Target As Range)
Dim CV As Boolean

If Worksheets("Sheet1").Range("A1").Value = "" Then CV = False
If CV = False Then Worksheets("Sheet2").CommandButton1.Enabled = False
If Worksheets("Sheet1").Range("A1").Value > 0 Then CV = True
If CV = True Then Worksheets("Sheet2").CommandButton1.Enabled = True
End Sub