Avoid warning about missing "override"

src/app/ui/editor/select_box_state.h

@@ -105,7 +105,7 @@ namespace app {
     virtual void getInvalidDecoratoredRegion(Editor* editor, gfx::Region& region) override;
 
     // Disable Shift+click to draw straight lines with the Pencil tool
-    virtual bool canCheckStartDrawingStraightLine() { return false; }
+    bool canCheckStartDrawingStraightLine() override { return false; }
 
   private:
     typedef std::vector<Ruler> Rulers;