Bug 153412 Change parameter type will cause preview fail
Description: Change parameter type will cause preview fail Steps to reproduce: 1. New a report paramter, string, text-box, default value is abc. 2. Drag the parameter to Layout and preview. 3. Change the parameter's type to integer, list-box, add a value 1 4. Preview Expected result: No errors. Actual result: The value "abc" is invalid with the type "integer".
UI/org.eclipse.birt.report.designer.ui.preview/src/org/eclipse/birt/report/designer/ui/preview/editors/ReportPreviewFormPage.java
public static final String SUFFIX_TEMPLATE_FILE = "rpttemplate"; 
	
	public static final String SUFFIX_DESIGN_CONFIG = "rptconfig"; 
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.designer.ui.editors.IReportEditorPage#onBroughtToTop(org.eclipse.birt.report.designer.ui.editors.IReportEditorPage)
	 */
	public boolean onBroughtToTop( IReportEditorPage prePage )
	{
		boolean isDisplay = false;
		if ( getEditorInput( ) != prePage.getEditorInput( ) )
		{
			setInput( prePage.getEditorInput( ) );
		}
		
		if ( isDirtyModel( ) )
		{
			doSave( null );
		}
		
		if ( prePage.isDirty( ) )
		{
			prePage.doSave( null );
		}
		
		if ( isMissingParameter( ) )
		{
			if ( parameterDialog != null )