VBA procedures do not appear in Macro dialog box

Description

In ArcMap, trying to run a VBA procedure using Tools > Macros > Macros, but the procedure does not appear in the list.

Cause

Procedures defined as private can not be run as macros.

Solution or Workaround

Code:
Public Sub TestMacro()
 MsgBox "This Macro Runs from the dialog"
End Sub