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 void style(Object widget) {
					engine.applyStyles((Widget) widget, true);
				}
				public CSSStyleDeclaration getStyle(Object widget) {
					Element e = engine.getCSSElementContext(widget)
							.getElement();
					if (e == null) {
						return null;
					}
					return engine.getViewCSS().getComputedStyle(e, null);
				}
				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);
				}
			});
			URL url;
			InputStream stream = null;
			try {
				url = FileLocator.resolve(new URL(cssURI));
				stream = url.openStream();
				engine.parseStyleSheet(stream);
			} catch (MalformedURLException e) {
				
				e.printStackTrace();