Hi, thank you for your message.
The actual behavior is the intended one.
The Runtime provided inside the Designer is indeed re-initialized at each Designer startup. This provides a way to keep a "clean" Runtime somewhere for you to test.
Most often, users setup a Runtime out of the Designer folder (or some server), and they customize it at will.
That being said, as we know that some users prefer to work with their local Runtime-of-the-Designer, we provide a mechanism for preventing the reset. Please read
this article
for more information.