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
|| expressionValue1.getText( ).trim( ).length( ) == 0 )
				{
					return false;
				}
			}
			if ( expressionValue2.getVisible( ) )
			{
				if ( expressionValue2.getText( ) == null
						|| expressionValue2.getText( ).trim( ).length( ) == 0 )
				{
					return false;
				}
			}
		}
		return true;
	}
	protected void checkAddButtonStatus( )
	{
		if ( addExpressionValue != null )
		{
			String value = addExpressionValue.getText( );
			if ( value == null
					|| value.length( ) == 0
					|| value.trim( ).length( ) == 0 )
			{
				addBtn.setEnabled( false );
				return;
			}
			if ( value != null )
			{