Put one of those functions back... I will need it in future.

src/Project.cpp

@@ -4623,6 +4623,11 @@ void AudacityProject::TP_RedrawScrollbars()
    FixScrollbars();
 }
 
+void AudacityProject::TP_HandleResize()
+{
+   HandleResize();
+}
+
 void AudacityProject::GetPlayRegion(double* playRegionStart,
                                     double *playRegionEnd)
 {

src/Project.h

@@ -406,6 +406,7 @@ class AUDACITY_DLL_API AudacityProject:  public wxFrame,
    virtual void TP_ScrollRight();
    virtual void TP_ScrollWindow(double scrollto);
    virtual void TP_ScrollUpDown(int delta);
+   virtual void TP_HandleResize();
 
    // ToolBar
 

src/TrackPanelListener.h

@@ -34,6 +34,7 @@ class AUDACITY_DLL_API TrackPanelListener {
    virtual void TP_ScrollRight() = 0;
    virtual void TP_ScrollWindow(double scrollto) = 0;
    virtual void TP_ScrollUpDown(int delta) = 0;
+   virtual void TP_HandleResize() = 0;
 };
 
 #endif