Eliminate idle event handler of CellularPanel...

... achieving the intent of b7386c2db1a136c4684f1e52e53d2f21262032dd by other
means

src/AdornedRulerPanel.cpp

@@ -948,6 +948,12 @@ AdornedRulerPanel::~AdornedRulerPanel()
 {
 }
 
+void AdornedRulerPanel::Refresh( bool eraseBackground, const wxRect *rect )
+{
+   CellularPanel::Refresh( eraseBackground, rect );
+   CellularPanel::HandleCursorForPresentMouseState();
+}
+
 void AdornedRulerPanel::UpdatePrefs()
 {
    if (mNeedButtonUpdate) {

src/AdornedRulerPanel.h

@@ -39,6 +39,10 @@ public:
 
    ~AdornedRulerPanel();
 
+   void Refresh
+      (bool eraseBackground = true, const wxRect *rect = (const wxRect *) NULL)
+      override;
+
    bool AcceptsFocus() const override { return s_AcceptsFocus; }
    bool AcceptsFocusFromKeyboard() const override { return true; }
    void SetFocusFromKbd() override;

src/CellularPanel.cpp

@@ -103,7 +103,6 @@ BEGIN_EVENT_TABLE(CellularPanel, OverlayPanel)
     EVT_SET_FOCUS(CellularPanel::OnSetFocus)
     EVT_KILL_FOCUS(CellularPanel::OnKillFocus)
     EVT_CONTEXT_MENU(CellularPanel::OnContextMenu)
-    EVT_IDLE(CellularPanel::OnIdle)
 END_EVENT_TABLE()
 
 CellularPanel::CellularPanel(
@@ -473,12 +472,6 @@ void CellularPanel::OnContextMenu(wxContextMenuEvent & WXUNUSED(event))
    DoContextMenu();
 }
 
-void CellularPanel::OnIdle(wxIdleEvent &event)
-{
-   event.Skip();
-   HandleCursorForPresentMouseState();
-}
-
 /// Handle mouse wheel rotation (for zoom in/out, vertical and horizontal scrolling)
 void CellularPanel::HandleWheelRotation( TrackPanelMouseEvent &tpmEvent )
 {

src/CellularPanel.h

@@ -141,8 +141,6 @@ private:
    
    void OnContextMenu(wxContextMenuEvent & event);
    
-   void OnIdle(wxIdleEvent & event);
-   
    void HandleInterruptedDrag();
    void Uncapture( bool escaping, wxMouseState *pState = nullptr );
    bool HandleEscapeKey(bool down);

src/TrackPanel.cpp

@@ -314,6 +314,12 @@ TrackPanel::TrackPanel(wxWindow * parent, wxWindowID id,
 
    theProject->Bind(EVT_UNDO_RESET, &TrackPanel::OnUndoReset, this);
 
+   wxTheApp->Bind(EVT_AUDIOIO_PLAYBACK,
+                     &TrackPanel::OnAudioIO,
+                     this);
+   wxTheApp->Bind(EVT_AUDIOIO_CAPTURE,
+                     &TrackPanel::OnAudioIO,
+                     this);
    UpdatePrefs();
 }
 
@@ -822,6 +828,15 @@ void TrackPanel::Refresh(bool eraseBackground /* = TRUE */,
       mRefreshBacking = true;
    }
    wxWindow::Refresh(eraseBackground, rect);
+
+   this->CellularPanel::HandleCursorForPresentMouseState();
+}
+
+void TrackPanel::OnAudioIO(wxCommandEvent & evt)
+{
+   evt.Skip();
+   // Some hit tests want to change their cursor to and from the ban symbol
+   CallAfter( [this]{ CellularPanel::HandleCursorForPresentMouseState(); } );
 }
 
 #include "TrackPanelDrawingContext.h"

src/TrackPanel.h

@@ -85,6 +85,8 @@ class AUDACITY_DLL_API TrackPanel final
 
    void UpdatePrefs() override;
 
+   void OnAudioIO(wxCommandEvent & evt);
+
    void OnPaint(wxPaintEvent & event);
    void OnMouseEvent(wxMouseEvent & event);
    void OnKeyDown(wxKeyEvent & event);