I create a limit called “en300328” (from 1GHz to 9.6GHz, limit is set > to -30dBm) and apply it to the graph.
When the frequency range is 2GHz to 9,6Ghz, i can see the limit, however, when i change the frequency range from 2,4GHz to 2,5GHz i cannot see the limit.
How can I see this limit curve?

This is a bug in the limit point interpolation formula and will be fixed in next release. At the moment simply add more limit points and it will work well.