In the results part, I have created some custom graphs from one test result and then I switch to another test. When the new test result is loaded, my graph are not updated with the new data. Is it normal?
You can graph statistics for any components from Virtual user to a single request. This allows you to quickly compare different data into a single graph.
If you switch from a test result to another, Neoload won't update the graph with the new data. It's a normal behavior. The goal is to be able to compare graphs from different test results.
By not updating the graph, you can then compare results from different test data.
For more information about graphs, see "Graphs" under "Results" section in Neoload documentation.