[568037] Handle ELK arrange all case with only one child in the diagram

Bug: 568037
Change-Id: I5db50cc412f74d3393406271ba8df1e5a8e60c2f
Signed-off-by: Laurent Redor <laurent.redor@obeo.fr>

1 files changed, 6 insertions, 1 deletions

diff --git a/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java b/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java
index 424bb1b102..ccbc8bb341 100644
--- a/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java
+++ b/plugins/org.eclipse.sirius.diagram.elk/src/org/eclipse/sirius/diagram/elk/ElkDiagramLayoutConnector.java
@@ -371,7 +371,12 @@ public class ElkDiagramLayoutConnector implements IDiagramLayoutConnector {
                             layoutRootPart = (IGraphicalEditPart) parent;
                         }
                     } else if (!(object instanceof ConnectionEditPart)) {
-                        layoutRootPart = (IGraphicalEditPart) object;
+                        if (selection.size() == 1 && isArrangeAll) {
+                            // Specific case of arrange all launch on a diagram with only one children
+                            layoutRootPart = getTopGraphicParentEditPartIfPresent((IGraphicalEditPart) object);
+                        } else {
+                            layoutRootPart = (IGraphicalEditPart) object;
+                        }
                     }
                 }
             }