Hi, i just want to share my solution for this problem. Some pleople say that you can easily fix it by pressing Esc, however this didn't work for me. I had tried before closing illustrator and opening it again, nothing happened. I even reset the preferences, it didn't work either.
I swear I was going INSANE.
I found out that its more like a bug of your PC, so when i closed all the windows/apps (all of them, no exception) and started Illustrator again, the problem was fix!!!
Hope this was helpul to anyone 🙂