clear instance selection on select click on nothing/something that isn't an instance

apps/opencs/view/render/editmode.cpp

@@ -2,6 +2,11 @@
 
 #include "worldspacewidget.hpp"
 
+CSVRender::WorldspaceWidget& CSVRender::EditMode::getWorldspaceWidget()
+{
+    return *mWorldspaceWidget;
+}
+
 CSVRender::EditMode::EditMode (WorldspaceWidget *worldspaceWidget, const QIcon& icon,
     unsigned int mask, const QString& tooltip, QWidget *parent)
 : ModeButton (icon, tooltip, parent), mWorldspaceWidget (worldspaceWidget), mMask (mask)

apps/opencs/view/render/editmode.hpp

@@ -17,6 +17,10 @@ namespace CSVRender
             WorldspaceWidget *mWorldspaceWidget;
             unsigned int mMask;
 
+        protected:
+
+            WorldspaceWidget& getWorldspaceWidget();
+
         public:
 
             EditMode (WorldspaceWidget *worldspaceWidget, const QIcon& icon, unsigned int mask,

apps/opencs/view/render/instancemode.cpp

@@ -3,6 +3,7 @@
 
 #include "elements.hpp"
 #include "object.hpp"
+#include "worldspacewidget.hpp"
 
 CSVRender::InstanceMode::InstanceMode (WorldspaceWidget *worldspaceWidget, QWidget *parent)
 : EditMode (worldspaceWidget, QIcon (":placeholder"), Element_Reference, "Instance editing",
@@ -30,6 +31,9 @@ void CSVRender::InstanceMode::selectPressed (osg::ref_ptr<TagBase> tag)
             // hit an Object, toggle its selection state
             CSVRender::Object* object = objectTag->mObject;
             object->setSelected (!object->getSelected());
+            return;
         }
     }
+
+    getWorldspaceWidget().clearSelection (Element_Reference);
 }