Bug 51608 project creation wizard: add folder button lets one add existing folder the first time
M7 test pass, I200402102000 1. Create a new java project 2. configure using src and bin folders 3. on the second page, press "add folder" 4. enter "src" as the folder name into the mask -> there is no complaint about the added folder, although it already existed -> when pressing "add folder" a second time, a different dialog comes up, allowing to specify where to add a new folder. Entering an existing folder name here gets flagged as an error. -> it seems that although there is an entry for the preconfigured "src" folder, it does not yet exist really.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/JavaProjectWizardSecondPage.java
fCanRemoveContent= false;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.jface.dialogs.IDialogPage#setVisible(boolean)
	 */
	public void setVisible(boolean visible) {
		if (visible) {
			changeToNewProject();
		} else {
			removeProject();
		}
		super.setVisible(visible);
	}
	
	private void changeToNewProject() {
		final IProject newProjectHandle= fFirstPage.getProjectHandle();
		final IPath newProjectLocation= fFirstPage.getLocationPath();
		
		fCanRemoveContent= !fFirstPage.getDetect();
		
		final boolean initialize= !(newProjectHandle.equals(fCurrProject) && newProjectLocation.equals(fCurrProjectLocation));
		
		final IRunnableWithProgress op= new IRunnableWithProgress() {
			public void run(IProgressMonitor monitor) throws InvocationTargetException {
				try {
					updateProject(initialize, monitor);
				} catch (CoreException e) {
					throw new InvocationTargetException(e);
				}