Hey, I just started out with Blueprints. I’m facing the same issue with the Player Controller blueprint in the default top down blueprint game. Same issue here, I’m not able to test anything out as the Blueprint is Read-only. I haven’t seen this issue raised anywhere else, so I just wanted to know if you found what the problem was in your case?
Also I’ve noticed now that when I tried this out in my own custom project or the marketplace projects, I didn’t face this issue. Even the default FPS project was not having this issue.
Edit: Sorry I made a silly mistake there, the blueprint became read-only because my level was already running in the editor. I just stopped it and now I can edit the blueprints.