Bug 57454 "show intro" preference not saved until shutdown
M8 As a general rule of thumb, if a plug-in changes a preference value then it should save it immediately. (or when the user hits OK/Apply in the prefs page, etc etc) When you start M8 and close the Intro page, I noticed that the ui.ide preferences are not saved until the workbench is shutdown.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/IDEWorkbenchAdvisor.java
page = win.openPage(id, getDefaultPageInput());
			} catch (WorkbenchException e) {
				ErrorDialog.openError(
					win.getShell(), 
					IDEWorkbenchMessages.getString("Problems_Opening_Page"), 
					e.getMessage(),
					e.getStatus());
			}
		}
		if (page == null)
			return;
	
		if (page.getPerspective() == null) {
			try {
				page = getWorkbenchConfigurer().getWorkbench().showPerspective(id, win);
			} catch (WorkbenchException e) {
				ErrorDialog.openError(
					win.getShell(),
					IDEWorkbenchMessages.getString("Workbench.openEditorErrorDialogTitle"),  
					IDEWorkbenchMessages.getString("Workbench.openEditorErrorDialogMessage"), 
					e.getStatus());
				return;
			}
		}
	
		page.setEditorAreaVisible(true);
	
		
		IEditorPart editor = page.findEditor(input);
		if (editor != null) {