Bug 310266 PartRenderingEngine shuts down when just one MWindow is destroyed
PartRenderingEngine's run(MApplicationElement, IEclipseContext) method has a big, inlined "HACK!!" comment in it. The problem is that it only checks for the disposal of one single shell. So if you have other shells hanging around (other MWindows), your whole application will be brought down even if you've only just closed one window.
bundles/org.eclipse.e4.ui.workbench.swt/src/org/eclipse/e4/ui/workbench/swt/internal/PartRenderingEngine.java
} else {
						
						testShell = new Shell(display, SWT.SHELL_TRIM);
						createGui((MUIElement) uiRoot, testShell);
					}
				}
				TestableObject testableObject = (TestableObject) runContext
						.get(TestableObject.class.getName());
				if (testableObject instanceof E4Testable) {
					((E4Testable) testableObject).init(display,
							(IWorkbench) runContext.get(IWorkbench.class
									.getName()));
				}
				
				while (testShell != null && !testShell.isDisposed()
						&& !display.isDisposed()) {
					try {
						if (!display.readAndDispatch()) {
							runContext.processWaiting();
							if (spinOnce)
								return;
							display.sleep();
						}
					} catch (ThreadDeath th) {
						throw th;
					} catch (Exception ex) {
						handle(ex, runContext);
					} catch (Error err) {
						handle(err, runContext);
					}