Basic Customization > User Interface Customization > Presenting Information in the UI > Creating Custom Graphical Representations > Limitations
  
Limitations
The internal names of graphical attributes must be used consistently throughout the system. Once you have chosen to use an attribute internal name for a graphical attribute on one type you should only use that attribute internal name for the same kind of graphical attribute anywhere you use it in the system.
If you reuse the same internal name for different purposes in this way you will see unexpected results where sometimes you do not get the graphical representation you expect or you get a graphical representation where you were not expecting one at all, or you get errors in the UI.
An attribute internal name must not be used across types for a mixture of graphical and non-graphical attributes. For example, you create an attribute named <myGraphicalAttr> on a document and make it a traffic light. You should not then create an attribute named <myGraphicalAttr> on part and make it an integer. Similarly you should not mix graphical attribute types with one internal name. You should not create an attribute called <myGraphicalAttr> on another type that is using a graphical representation other than traffic light.
Making mixed use of an attribute internal name is not supported.