A WTPart can have different view versions (e.g. Design View, Manufacturing View, Reduced View, etc.).
To be able to differentiate the view versions better and to avoid selecting the wrong ones (e.g. in the Resulting Objects of a Change Notice...), these should have different icons.
It becomes even more complex / confusing if you work also with different WTPart subtypes and you have for each subtype the possibility to have the different view versions. Therefore a different icon / marker in the icon for different view versions would be helpful.