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.swt/src/org/eclipse/e4/ui/internal/workbench/swt/PartRenderingEngine.java
engine.applyStyles((Widget) widget, true);
				}
				public CSSStyleDeclaration getStyle(Object widget) {
					return engine.getStyle((Widget) widget);
				}
				public void setClassnameAndId(Object widget, String classname,
						String id) {
					((Widget) widget).setData(
							"org.eclipse.e4.ui.css.CssClassName", classname); 
					((Widget) widget).setData("org.eclipse.e4.ui.css.id", id); 
					engine.applyStyles((Widget) widget, true);
				}
			});
		} else if (cssURI != null) {
			String cssResourcesURI = (String) appContext
					.get(E4Workbench.CSS_RESOURCE_URI_ARG);
			final CSSSWTEngineImpl engine = new CSSSWTEngineImpl(display, true);
			if (cssResourcesURI != null) {
				engine.getResourcesLocatorManager().registerResourceLocator(
						new OSGiResourceLocator(cssResourcesURI.toString()));
			}
			display.setData("org.eclipse.e4.ui.css.context", appContext); 
			appContext.set(IStylingEngine.SERVICE_NAME, new IStylingEngine() {
				public void setClassname(Object widget, String classname) {
					((Widget) widget).setData(
							"org.eclipse.e4.ui.css.CssClassName", classname); 
					engine.applyStyles((Widget) widget, true);
				}
				public void setId(Object widget, String id) {
					((Widget) widget).setData("org.eclipse.e4.ui.css.id", id);