Store a string identifier in each menu item...

... which is not yet used for anything.

It could be used to describe textual paths for attaching plug-in menu items.

Strings are only path local, not necessarily globally unique, and may be
left empty for separators and for groups that should be transparent to
path identification.

It may also be empty for certain sub-menus, such as those that group effects
according to the changeable criteria in Preferences.

src/menus/LabelMenus.cpp

@@ -561,6 +561,7 @@ static CommandHandlerObject &findCommandHandler(AudacityProject &) {
 
 #define FN(X) (& LabelEditActions::Handler :: X)
 
+// Under /MenuBar/Edit
 MenuTable::BaseItemSharedPtr LabelEditMenus()
 {
    using namespace MenuTable;
@@ -576,9 +577,9 @@ MenuTable::BaseItemSharedPtr LabelEditMenus()
    
    static BaseItemSharedPtr menus{
    FinderScope( findCommandHandler ).Eval(
-   Items(
+   Items( wxEmptyString,
    
-   Menu( XO("&Labels"),
+   Menu( wxT("Labels"), XO("&Labels"),
       Command( wxT("EditLabels"), XXO("&Edit Labels..."), FN(OnEditLabels),
                  AudioIONotBusyFlag ),
 
@@ -608,7 +609,7 @@ MenuTable::BaseItemSharedPtr LabelEditMenus()
 
    /////////////////////////////////////////////////////////////////////////////
 
-   Menu( XO("La&beled Audio"),
+   Menu( wxT("Labeled"), XO("La&beled Audio"),
       /* i18n-hint: (verb)*/
       Command( wxT("CutLabels"), XXO("&Cut"), FN(OnCutLabels),
          AudioIONotBusyFlag | LabelsSelectedFlag | WaveTracksExistFlag |