Bug 63255 [Preferences] some pages cannot be displayed in high contrast
STEPS 1) Switch to High Contrast by selecting Window->Control Panl->Accessibility Resources 2) Start Eclipse 3) Open the preferences page 4) Select Colors and Fonts 5) Select a diffrent page 6) new page not displayed.
bundles/org.eclipse.jface/src/org/eclipse/jface/preference/PreferenceDialog.java
*/
	protected void layoutTreeAreaControl(Control control) {
		GridData gd = new GridData(GridData.FILL_VERTICAL);
		gd.widthHint = getLastTreeWidth();
		gd.verticalSpan = 1;
		control.setLayoutData(gd);
	}
	/**
	 * The preference dialog implementation of this <code>Dialog</code>
	 * framework method sends <code>performOk</code> to all pages of the
	 * preference dialog, then calls <code>handleSave</code> on this dialog to
	 * save any state, and then calls <code>close</code> to close this dialog.
	 */
	protected void okPressed() {
		Platform.run(new SafeRunnable() {
			private boolean errorOccurred;
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.core.runtime.ISafeRunnable#run()
			 */
			public void run() {
				getButton(IDialogConstants.OK_ID).setEnabled(false);
				errorOccurred = false;
				try {
					
					Iterator nodes = preferenceManager.getElements(
							PreferenceManager.PRE_ORDER).iterator();
					while (nodes.hasNext()) {
						IPreferenceNode node = (IPreferenceNode) nodes.next();