Add Text Box - Text Disappears, but still in comment box

Whenever I use the 'Add Text Box' feature under Tools, I can change font, color, size of text, but as soon as I click on the document to add another text box, the text from the first box disappears but still shows up in the comment list.  I used to be able to add text comments with no problem, but I have tried adding text boxes to numerous documents and same thing happens every time.  I have looked through all the settings and cannot figure out if something is making them disappear.  I also tried 'Repair Acrobat Installation' but that did not help.  I am using Adobe Acrobat X Pro.