Bug 167812 Clear history result of table preview
Create a table with data in the cells. Preview the table. If we delete a column from the table and preview again, the preview screen shows the previous table first then refreshes and shows the updated table. This confuses the user whether the table got updated or not. In the case where table data is really big, user might not wait for the preview to reload. Show the blank page every time the user previews the report to avoid confusion.
UI/org.eclipse.birt.report.designer.ui.preview/src/org/eclipse/birt/report/designer/ui/preview/editors/ReportPreviewFormPage.java
/*************************************************************************************
 * Copyright (c) 2004 Actuate Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     Actuate Corporation - Initial implementation.
 ************************************************************************************/
package org.eclipse.birt.report.designer.ui.preview.editors;
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;