Text not visible in Terminal

I have recently been having problems using Terminal in Coda. The text is not visible. It is there but I only see it if I highlight the lines that are there and click on the selected content and drag it, then it becomes visible. I’ve checked the background and foreground colours and they are set correctly, black for background and white for text. When I tried a few days ago it worked fine and then today it is back to text not being visible. Does anyone have any suggestions?