Fix crash when dragging something from another task over the editor window.

git-svn-id: svn://localhost/ardour2/branches/3.0@7107 d708f5d6-7413-0410-9779-e7cbd77b26cf

2 files changed, 9 insertions, 1 deletions

diff --git a/libs/gtkmm2ext/dndtreeview.cc b/libs/gtkmm2ext/dndtreeview.cc
index 0695dd3281..179423f203 100644
--- a/libs/gtkmm2ext/dndtreeview.cc
+++ b/libs/gtkmm2ext/dndtreeview.cc
@@ -69,6 +69,7 @@ bool
 DnDTreeViewBase::on_drag_drop(const Glib::RefPtr<Gdk::DragContext>& context, int x, int y, guint time)
 {
 	suggested_action = Gdk::DragAction (0);
+	drag_data.source = 0;
 	return TreeView::on_drag_drop (context, x, y, time);
 }
 
diff --git a/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h b/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h
index 6295377672..b5f18fa890 100644
--- a/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h
+++ b/libs/gtkmm2ext/gtkmm2ext/dndtreeview.h
@@ -70,6 +70,8 @@ class DnDTreeViewBase : public Gtk::TreeView
 	std::string                 object_type;
 
 	struct DragData {
+	    DragData () : source (0) {}
+		
 	    Gtk::TreeView* source;
 	    int            data_column;
 	    std::string    object_type;
@@ -134,11 +136,16 @@ class DnDTreeView : public DnDTreeViewBase
 	}
 
 	/**
-	 * this can be called by the Treeview itself or by some other
+	 * This can be called by the Treeview itself or by some other
 	 * object that wants to get the list of dragged items.
 	 */
 
 	void get_object_drag_data (std::list<DataType>& l, Gtk::TreeView** source) {
+
+		if (drag_data.source == 0) {
+			return;
+		}
+			
 		Glib::RefPtr<Gtk::TreeModel> model = drag_data.source->get_model();
 		DataType v;
 		Gtk::TreeSelection::ListHandle_Path selection = drag_data.source->get_selection()->get_selected_rows ();