New preference for pinned play head, also in Transport menu

src/toolbars/ControlToolBar.cpp

@@ -68,6 +68,7 @@
 #include "../widgets/Meter.h"
 
 #include "../tracks/ui/Scrubbing.h"
+#include "../prefs/PlaybackPrefs.h"
 
 IMPLEMENT_CLASS(ControlToolBar, ToolBar);
 
@@ -635,15 +636,16 @@ int ControlToolBar::PlayPlayRegion(const SelectedRegion &selectedRegion,
                NoteTrackArray(),
 #endif
                tcp0, tcp1, myOptions);
-         } else
-         {
+         }
+         else {
             // Cannot create cut preview tracks, clean up and exit
             SetPlay(false);
             SetStop(false);
             SetRecord(false);
             return -1;
          }
-      } else {
+      }
+      else {
          // Lifted the following into AudacityProject::GetDefaultPlayOptions()
          /*
          if (!timetrack) {
@@ -682,6 +684,8 @@ int ControlToolBar::PlayPlayRegion(const SelectedRegion &selectedRegion,
       return -1;
    }
 
+   StartScrollingIfPreferred();
+
    // Let other UI update appearance
    if (p)
       p->GetRulerPanel()->HideQuickPlayIndicator();
@@ -1076,6 +1080,8 @@ void ControlToolBar::OnRecord(wxCommandEvent &evt)
       if (success) {
          p->SetAudioIOToken(token);
          mBusyProject = p;
+
+         StartScrollingIfPreferred();
       }
       else {
          if (shifted) {
@@ -1263,6 +1269,14 @@ void ControlToolBar::UpdateStatusBar(AudacityProject *pProject)
    pProject->GetStatusBar()->SetStatusText(StateForStatusBar(), stateStatusBarField);
 }
 
+void ControlToolBar::StartScrollingIfPreferred()
+{
+   if (PlaybackPrefs::GetPinnedHeadPreference())
+      StartScrolling();
+   else
+      StopScrolling();
+}
+
 void ControlToolBar::StartScrolling()
 {
    using Mode = AudacityProject::PlaybackScroller::Mode;

src/toolbars/ControlToolBar.h

@@ -107,6 +107,7 @@ class ControlToolBar final : public ToolBar {
    void UpdateStatusBar(AudacityProject *pProject);
 
    // Starting and stopping of scrolling display
+   void StartScrollingIfPreferred();
    void StartScrolling();
    void StopScrolling();