skins2: drag&drop (small tweak)

Rather than automatically expanding folders when hoving over them, use this
information (folder expanded or not) to either insert the dropped item as its
next sibling in the parent folder or as its first child in this folder respectively.

modules/gui/skins2/controls/ctrl_tree.cpp

@@ -504,8 +504,6 @@ void CtrlTree::handleEvent( EvtGeneric &rEvent )
         Iterator it = findItemAtPos( yPos );
         if( it != m_itOver )
         {
-            if( it != m_rTree.end() )
-                it->setExpanded( true );
             m_itOver = it;
             needRefresh = true;
         }

modules/gui/skins2/vars/playtree.cpp

@@ -290,7 +290,7 @@ void Playtree::insertItems( VarTree& elem, const list<string>& files, bool start
         p_node = m_pPlaylist->p_ml_category;
         i_pos = 0;
     }
-    else if( p_elem->size() )
+    else if( p_elem->size() && p_elem->isExpanded() )
     {
         p_node = playlist_ItemGetById( m_pPlaylist, p_elem->getId() );
         i_pos = 0;