ST6RI-697 Feature chains in Action or Interconnection views are not properly rendered

[himi]

The visualizer could not properly render feature chains in behavioural rendering, used by Action, State, Interconnection, Case views. The example below

action a {
    action a1 {
        action a11;
    }
    action a12;
    first a1.a11 then a12;
}

is wrongly rendered as:

[himi]

After the fix, the example is correctly rendered as: