Can edit used color

[Lena Ernstsen]

It is possible to edit a product color that is already used in the net. This makes the net invalid and results in an error when trying to verify a query.

How to reproduce:
  - Create a colored net with a product color consisting of 1 dot
  - Add a place and transition connected by an arc
  - Make a guard on a transition with the product color
  - Edit the product color to consist of 2 dot
  - Verify a query
A verification error will occur saying "COULD NOT FIND PRODUCT TYPE".

[Jiri Srba (srba)]

I cannot reproduce the error. What exact guard should I create?

[Jiri Srba (srba)]

Also, please. modify the message "Colortype cannot have colors removed for the following reasons:" to "The color type cannot be modified for the following reasons: "