Hi Chris,
Are you running the newest 2.2.6.5 version? I think this issue about it dissapearing was fixed as discussed in this thread.
In the latest version the markup renders some classes on the text boxes which can be styled:
.smalltextbox { width: 4em; }
.normaltextbox { width: 10em; }
.mediumtextbox { width: 15em; }
.widetextbox { width: 25em; }
.verywidetextbox { width: 35em; }
However, even without those class names you can create css selectors to style text boxes. You could put borders on all of them like this:
input[type="text"] { border: solid thin black; }
or if you just want it on admin pages:
.admin input[type="text"] { border: solid thin black; }
Hope it helps,
Joe