Defer cursor winrt event triggering

src/buffer/out/cursor.cpp

@@ -315,6 +315,11 @@ void Cursor::StartDeferDrawing() noexcept
     _fDeferCursorRedraw = true;
 }
 
+bool Cursor::IsDeferDrawing() noexcept
+{
+    return _fDeferCursorRedraw;
+}
+
 void Cursor::EndDeferDrawing() noexcept
 {
     if (_fHaveDeferredCursorRedraw)

src/buffer/out/cursor.h

@@ -55,6 +55,7 @@ class Cursor final
     const COLORREF GetColor() const noexcept;
 
     void StartDeferDrawing() noexcept;
+    bool IsDeferDrawing() noexcept;
     void EndDeferDrawing() noexcept;
 
     void SetHasMoved(const bool fHasMoved) noexcept;

src/cascadia/TerminalCore/Terminal.cpp

@@ -1070,7 +1070,12 @@ void Terminal::_AdjustCursorPosition(const COORD proposedPosition)
         _buffer->GetRenderTarget().TriggerScroll(&delta);
     }
 
-    _NotifyTerminalCursorPositionChanged();
+    // Firing the CursorPositionChanged event is very expensive so we try not to do that when
+    // the cursor does not need to be redrawn.
+    if (!cursor.IsDeferDrawing())
+    {
+        _NotifyTerminalCursorPositionChanged();
+    }
 }
 
 void Terminal::UserScrollViewport(const int viewTop)