Ive got a macro in an addin thats installed in excel 2003 and I want to
assign a button to that sub. When I try to assign it to a button I can not
see it in the macro selection box. I have it as a public sub as follows:

Public Sub MergeFormatCells()
With Selection
.HorizontalAlignment = xlGeneral
.VerticalAlignment = xlTop
.WrapText = True
.Orientation = 0
.AddIndent = False
.IndentLevel = 0
.ShrinkToFit = False
.ReadingOrder = xlContext
.MergeCells = True
End With
End Sub

Im trying to assign this to the excel toolbar button for all workbook and
not just assign it to one workbook.