Added SplitPane to separate the 3D scene and the tree view

src/main/java/fr/ill/ics/n3d/Nomad3DEditor.java

@@ -47,6 +47,7 @@ import javafx.scene.control.TreeItem;
 import javafx.scene.control.TreeView;
 import javafx.scene.input.KeyCode;
 import javafx.scene.layout.BorderPane;
+import javafx.scene.control.SplitPane;
 import javafx.scene.layout.StackPane;
 import javafx.scene.paint.Color;
 import javafx.scene.paint.PhongMaterial;
@@ -183,19 +184,25 @@ public class Nomad3DEditor extends Application {
 			// ---------------
 			StackPane subScenePane = new StackPane(subScene);
 			subScenePane.setPrefSize(subScene.getWidth(), subScene.getHeight());
+			subScene.setManaged(false);
 			subScene.widthProperty().bind(subScenePane.widthProperty());
 			subScene.heightProperty().bind(subScenePane.heightProperty());
 			TreeView<Component> hierarchyView = buildHierarchyView();
-			
+						
 			pane = new BorderPane();
-		    pane.setCenter(subScenePane);
+			
+			SplitPane splitPane = new SplitPane();
+			splitPane.getItems().addAll(hierarchyView, subScenePane);
+			splitPane.setDividerPosition(0, 0.3);
+			
+			pane.setCenter(splitPane);
 	        pane.setTop(buildMenuBar());
-			pane.setLeft(hierarchyView);
 			
 			scene = new Scene(pane);
 			scene.setFill(Color.WHITE);
 			
 			buildEventHandlers(null);
+			
 		} else {
 			scene = loadScene(initialModelPath);
 		}
@@ -377,6 +384,7 @@ public class Nomad3DEditor extends Application {
 		subScene.setFill(Color.color(0.5, 0.55, 0.65));
 		StackPane subScenePane = new StackPane(subScene);
 		subScenePane.setPrefSize(subScene.getWidth(), subScene.getHeight());
+		subScene.setManaged(false);
 		subScene.widthProperty().bind(subScenePane.widthProperty());
 		subScene.heightProperty().bind(subScenePane.heightProperty());
 	
@@ -388,11 +396,14 @@ public class Nomad3DEditor extends Application {
 			
 		TreeView<Component> hierarchyView = buildHierarchyView();
 		
-
 		this.pane = new BorderPane();
+        	    
+		SplitPane splitPane = new SplitPane();
+		splitPane.getItems().addAll(hierarchyView, subScenePane);
+		splitPane.setDividerPosition(0, 0.3);
+		
+		pane.setCenter(splitPane);
         pane.setTop(buildMenuBar());
-	    pane.setCenter(subScenePane);
-	    pane.setLeft(hierarchyView);
 		
 		this.scene = new Scene(pane);
 		scene.setFill(Color.WHITE);