I was lucky to have a boss once who was a great leader and just like you said in your post, whenever I had a problem at work he was expecting me to come up with a solution (or at least an idea of how I could solve it). He never said that his door was open, but he didn't need to, which it's strange now that I think about it. How could he make us feel that without saying it. It was the first time I had a boss making me feel that I had a saying in how I should solve certain situations and at first I remember it felt a bit overwhelming, but I grew as a professional and as a person. I remember him with great affection❤️.