Bug 312859 The list of operator for Chart filter does not provide 30 visible items
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/dialogs/ChartCubeFilterConditionBuilder.java
this.expressionProvider = provider;
		setColumnList( this.designHandle );
	}
	/*
	 * Return the hanle of Map Rule builder
	 */
	public FilterConditionElementHandle getInputHandle( )
	{
		return inputHandle;
	}
	/**
	 * Refreshes the OK button state.
	 * 
	 */
	protected void updateButtons( )
	{
		enableInput( isExpressionOK( ) );
		if ( getButton( IDialogConstants.OK_ID ) != null )
		{
			getButton( IDialogConstants.OK_ID ).setEnabled( isConditionOK( ) );
		}
	}
	protected void enableInput( boolean val )
	{
		operator.setEnabled( val );
		if ( valueVisible != 3 )
		{
			if ( expressionValue1 != null )
				expressionValue1.setEnabled( val );
			if ( expressionValue2 != null )