Prevent duplication of time tracks via track menu

Previously, it was possible to duplicate a time track via the track
options menu and clicking on "Duplicate Entire Track". However, Tenacity
only allows one time track per project. This issue has now been fixed by
checking for the presence of a time track.

Signed-off-by: Avery King <[email protected]>

src/tracks/ui/CommonTrackControls.cpp

@@ -20,6 +20,7 @@ Paul Licameli split from TrackControls.cpp
 #include "Project.h"
 #include "../../ProjectHistory.h"
 #include "../../ProjectWindows.h"
+#include "../../TimeTrack.h"
 #include "../../TrackArtist.h"
 #include "../../TrackInfo.h"
 #include "../../TrackPanelDrawingContext.h"
@@ -29,6 +30,7 @@ Paul Licameli split from TrackControls.cpp
 #include "../../commands/AudacityCommand.h"
 #include "../../commands/CommandManager.h"
 #include "../../shuttle/ShuttleGui.h"
+#include "../../widgets/AudacityMessageBox.h"
 #include "../../widgets/PopupMenuTable.h"
 
 #include <wx/dc.h>
@@ -263,6 +265,16 @@ void TrackMenuTable::OnDuplicateTrack(wxCommandEvent&)
    {
       TenacityProject& project = mpData->project;
       TrackList& tracks = TrackList::Get(project);
+
+      if (*tracks.Any<TimeTrack>().begin())
+      {
+         AudacityMessageBox(
+            XO("This version of Tenacity only allows one time track for each project window.")
+         );
+
+         return;
+      }
+
       auto dupTrack = track->Duplicate();
       tracks.Add(dupTrack);