rem: if ( dest_path )
add: if ( dest_path && selection_data )
context: gboolean categ_row_drop_possible ( GtkTreeDragDest * drag_dest, GtkTreePath * dest_path,				   GtkSelectionData * selection_data ){    if ( dest_path )    {	GtkTreePath * orig_path;	GtkTreeModel * model;	enum meta_tree_row_type orig_type, dest_type;	gtk_tree_get_row_drag_data (selection_data, &model, &orig_path);	orig_type = metatree_get_row_type ( GTK_TREE_MODEL(categ_tree_model), orig_path );	dest_type = metatree_get_row_type ( GTK_TREE_MODEL(categ_tree_model), dest_path );	switch ( orig_type )	{	    case META_TREE_SUB_DIV:		if ( dest_type == META_TREE_DIV )		    return TRUE;		break;	    case META_TREE_TRANSACTION:		if ( dest_type == META_TREE_DIV || 		     dest_type == META_TREE_SUB_DIV )		    return TRUE;		break;	    default:		break;	}    }    return FALSE;}