Bug 41927 [Dialogs] Selecting in PreferenceDialog generates too many invalid entries
20030825 If you select an entry, close the dialog and then reopen it selecting anotehr entry will result in a "this page has invalid values" although you selected nothing.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
}
	/* (non-Javadoc)
	 * Method declared on Dialog.
	 */
	protected Control createDialogArea(Composite parent) {
		GridData gd;
		Composite composite = (Composite) super.createDialogArea(parent);
		((GridLayout) composite.getLayout()).numColumns = 2;
		((GridLayout) composite.getLayout()).horizontalSpacing = 10;
		
		createTree(composite);
		gd = new GridData(GridData.FILL_VERTICAL);
		gd.widthHint = 150;
		gd.verticalSpan = 2;
		tree.setLayoutData(gd);
		
		Composite titleComposite = new Composite(composite, SWT.NONE);
		GridLayout layout = new GridLayout();
		layout.marginHeight = 0;
		layout.marginWidth = 0;
		layout.verticalSpacing = 0;
		layout.horizontalSpacing = 0;
		titleComposite.setLayout(layout);
		titleComposite.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
		createTitleArea(titleComposite);
		
		pageContainer = createPageContainer(composite);
		pageContainer.setLayoutData(new GridData(GridData.FILL_BOTH));
		
		Label separator = new Label(composite, SWT.HORIZONTAL | SWT.SEPARATOR);