[531513] Avoid NPE if the border color of the style is null

Bug: 531513
Change-Id: I7496497ea448eea75d9b4c244c7dac3d76bd6024
Signed-off-by: Maxime Porhel <maxime.porhel@obeo.fr>
diff --git a/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/figure/ContainerWithTitleBlockFigure.java b/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/figure/ContainerWithTitleBlockFigure.java
index da3d871..1b2d4af 100644
--- a/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/figure/ContainerWithTitleBlockFigure.java
+++ b/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/figure/ContainerWithTitleBlockFigure.java
@@ -181,7 +181,9 @@
     private Color geBorderColor() {
         if (viewNode.getStyle() instanceof BorderedStyle) {
             RGBValues borderColor = ((BorderedStyle) viewNode.getStyle()).getBorderColor();
-            return new Color(null, borderColor.getRed(), borderColor.getGreen(), borderColor.getBlue());
+            if (borderColor != null) {
+                return new Color(null, borderColor.getRed(), borderColor.getGreen(), borderColor.getBlue());
+            }
         }
         return ColorConstants.black;
     }