Bug 80833 [Import/Export] Import exisiting should pre-check for project already in workspace
While it is good that it lets you import projects in the default workspace location, it should not let you select projects that already exist in the workspace (since importing such a project will fail). When searching for .project files in the file system, it could use IWorkspaceRoot.findFilesForLocation followed by checking IFile.exists() to filter out .project files for existing projects.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/wizards/datatransfer/WizardProjectsImportPage.java
*/
	public WizardProjectsImportPage(String pageName, String title,
			ImageDescriptor titleImage) {
		super(pageName, title, titleImage);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.dialogs.IDialogPage#createControl(org.eclipse.swt.widgets.Composite)
	 */
	public void createControl(Composite parent) {
		initializeDialogUnits(parent);
		Composite workArea = new Composite(parent, SWT.NONE);
		setControl(workArea);
		workArea.setLayout(new GridLayout());
		workArea.setLayoutData(new GridData(GridData.FILL_BOTH
				| GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL));
		createProjectsRoot(workArea);
		createProjectsList(workArea);
		createOptionsArea(workArea);
		restoreWidgetValues();
		Dialog.applyDialogFont(workArea);
	}
	
	/**
	 * Create the area with the extra options.
	 * @param workArea
	 */
	private void createOptionsArea(Composite workArea){
		Composite optionsGroup = new Composite(workArea, SWT.NONE);