There is a known fault in the Adobe marketplace add-on installation process which may result in a blank window displayed for some users using a Windows operating system. Adobe has been made aware of this issue.
For example, you may see this:
Follow these steps
Note: You may need to have administrator access to your computer to carry out some of these steps.
Navigate to c:\Program Files (x86)\Common Files\Adobe\CEP\extensions.
Right mouse click the folder PagePoofCC and select properties.
Select the Security tab and in Group or user names select your user name, then click Edit...
Note: You may need to enter a password.
In Permissions for Users ensure Allow is checked on next to Full Control, then click Apply and OK to close the windows.
Re-launch your Adobe application, and the PageProof add-on will show your dashboard content.