Something has gone wrong with the editor!!

I tried to change some wording - highlighting a text box and making some changes. Then I was stuck in that box! I stayed outlined in yellow and I couldn't get anyplace else. I went to full screen and that box was now in the wrong place and didn't relate anymore with the box of text. So I can't change anything right! And it saved this error situation when I tried to escape without a change. What's going wrong?!?