An orange exclamation point 
appearing at the top-right of your viewlet is a warning. Hover over the icon to view the warning message. Usually this message means that there was more data than XRay retrieved from the back-end.
Example
In the example below, the number of generated chart graphs is limited to 100. The warning message, Drawing first [100] out of [147] graphs, is displayed. It is alerting you that there are more than 100 graphs.
The warning message can contain multiple alerts.