diff --git a/src/GUI/MainFrame.hpp b/src/GUI/MainFrame.hpp
index 3c474a9..eb53aa2 100644
--- a/src/GUI/MainFrame.hpp
+++ b/src/GUI/MainFrame.hpp
@@ -183,6 +183,9 @@ class MainFrame : public wxFrame
         // -------------------------------------------------------------------
         wxLongLong m_LoopA, m_LoopB;
 
+        // -------------------------------------------------------------------
+        wxSystemAppearance m_Theme = wxSystemSettings::GetAppearance();
+
     private:
         // -------------------------------------------------------------------
         bool bAutoplay = false;
@@ -259,6 +262,10 @@ class MainFrame : public wxFrame
         // Frame resize event handler
         void OnResizeFrame(wxSizeEvent& event);
 
+        // Splitter window sash pos event handler
+        void OnTopSplitterSashPosChanged(wxSplitterEvent& event);
+        void OnBottomSplitterSashPosChanged(wxSplitterEvent& event);
+
         // -------------------------------------------------------------------
         // Timer update event handler
         void UpdateElapsedTime(wxTimerEvent& event);