Bug 327033 Workbench doesn't relayout after a stack disappears
If you close all the views of a stack, you just get an empty rectangle of space now. Resizing your window will adjust the layout properly. Note that reopening the views don't help, you still have to resize something to force a layout.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/SashRenderer.java
return;
				}
				if (UIEvents.GenericTile.HORIZONTAL.equals(event
						.getProperty(UIEvents.EventTags.ATTNAME))) {
					Boolean horizontal = (Boolean) event
							.getProperty(UIEvents.EventTags.NEW_VALUE);
					MPartSashContainer container = (MPartSashContainer) element;
					SashForm sashForm = (SashForm) container.getWidget();
					sashForm.setOrientation(horizontal.booleanValue() ? SWT.HORIZONTAL
							: SWT.VERTICAL);
				}
			}
		};
		eventBroker.subscribe(UIEvents.buildTopic(UIEvents.GenericTile.TOPIC,
				UIEvents.GenericTile.HORIZONTAL), sashOrientationHandler);
		sashWeightHandler = new EventHandler() {
			public void handleEvent(Event event) {
				
				MUIElement element = (MUIElement) event
						.getProperty(UIEvents.EventTags.ELEMENT);
				MUIElement parent = element.getParent();
				if (!(parent instanceof MPartSashContainer)
						|| parent.getRenderer() != SashRenderer.this)
					return;
				MElementContainer<MUIElement> pscModel = (MElementContainer<MUIElement>) parent;
				if (UIEvents.UIElement.CONTAINERDATA.equals(event
						.getProperty(UIEvents.EventTags.ATTNAME))) {
					forceLayout(pscModel);
				}
			}