You would need VBA event code to add the filldown command to right-click.
How about just go to Tools>Customize>Commands>Edit and drag the FillDown button
to a toolbar?
For the event code................
Sub fill()
Selection.FillDown
End Sub
Sub fill() goes into a general module.
The following two events go into the Thisworkbook module.
I suggest you open a new workbook, copy the macro and event code into that
workbook then Save As an Add-in which loads when Excel starts.
If you go that route, you don't really need the BeforeClose event.
Sub Workbook_Open()
With Application.CommandBars("Cell").Controls.Add(temporary:=True)
.BeginGroup = True
.Caption = "Fill Down"
.OnAction = "Fill"
End With
End Sub
Private Sub Workbook_BeforeClose(Cancel As Boolean)
Application.CommandBars("Cell").Controls("Fill Down").Delete
End Sub
Gord Dibben MS Excel MVP