Summary
If you cannot see a page displayed when you open a document in AppXtender (it's just an empty grey space), please clear your browser’s history, cookies, and cache memory -- then close out your browser and open a new browser session -- this solution will fix the issue.
Body
ERROR: There is no error message, but when I open a document, the page is not displaying in the space where I normally see the page -- even when I click on the thumbnail. It just displays a blank gray space. See screen shot below:
ISSUE: This issue is related to the AppXtender upgrade and some leftover files from the previous version of AppXtender are causing issues interpreting the new upgraded version of AppXtender.
SOLUTION: Please clear your browser’s history, cookies, and cache memory -- then close out your browser and open a new browser session -- this solution will fix the issue. Please see the following link "How to clear your browsers history cookies and cache memory" for instructions.