Bug 318498 Many toolbars on top of one another
I don't know how to reproduce this. I'll attach a screenshot.
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/LazyStackRenderer.java
MUIElement ref = ph.getRef();
			ref.setCurSharedRef(ph);
			Composite phComp = (Composite) ph.getWidget();
			Control refCtrl = (Control) ph.getRef().getWidget();
			refCtrl.setParent(phComp);
			phComp.layout(new Control[] { refCtrl }, SWT.DEFER);
			if (ref instanceof MPart
					&& ph.getParent().getWidget() instanceof CTabFolder) {
				
				MPart part = (MPart) ref;
				CTabFolder ctf = (CTabFolder) ph.getParent().getWidget();
				MToolBar tbModel = part.getToolbar();
				if (tbModel != null && tbModel.getWidget() != null) {
					ToolBar oldTB = (ToolBar) tbModel.getWidget();
					if (oldTB.getParent() instanceof CTabFolder) {
						CTabFolder oldCTF = (CTabFolder) oldTB.getParent();
						if (oldCTF.getTopRight() == oldTB)
							oldCTF.setTopRight(null);
					}
					oldTB.setParent(ctf);
					ctf.setTopRight(oldTB);
				}
			}
			element = ref;
		}
		if (element instanceof MContext) {
			IEclipseContext context = ((MContext) element).getContext();
			if (context != null) {
				IEclipseContext newParentContext = modelService
						.getContainingContext(element);