Bug 314317 Cannot re-create a previously closed MWindow instance
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/workbench/ui/renderers/swt/WBWRenderer.java
.getShell();
		IEclipseContext parentContext = getContextForParent(element);
		final Shell wbwShell;
		if (parentShell == null) {
			wbwShell = new Shell(Display.getCurrent(), SWT.SHELL_TRIM);
		} else if (wbwModel.getTags().contains("dragHost")) { 
			wbwShell = new Shell(parentShell, SWT.BORDER);
			wbwShell.setAlpha(110);
		} else {
			wbwShell = new Shell(parentShell, SWT.TOOL | SWT.TITLE | SWT.MAX
					| SWT.RESIZE);
		}
		wbwShell.setBackgroundMode(SWT.INHERIT_DEFAULT);
		wbwShell.setBounds(wbwModel.getX(), wbwModel.getY(),
				wbwModel.getWidth(), wbwModel.getHeight());
		setCSSInfo(wbwModel, wbwShell);
		
		IEclipseContext localContext = getContext(wbwModel);
		parentContext.set(IContextConstants.ACTIVE_CHILD, localContext);
		
		CSSEngineHelper helper = new CSSEngineHelper(localContext, wbwShell);
		TrimmedPartLayout tl = new TrimmedPartLayout(wbwShell);
		tl.gutterTop = helper.getMarginTop(0);
		tl.gutterBottom = helper.getMarginBottom(0);
		tl.gutterLeft = helper.getMarginLeft(0);
		tl.gutterRight = helper.getMarginRight(0);
		wbwShell.setLayout(tl);
		newWidget = wbwShell;
		bindWidget(element, newWidget);