Dclocks, I have not been hearing this said elsewhere - and this seems to be borne out by the lack of response from others in this rather busy forum who are experiencing the same thing.
In my experience, this sort of thing may respond to some simple 'fixes' such as the following - which are not sequential, by the way:
* Rebooting your computer if your rarely do that. (It astonishes me, sometimes, what this will set right.)
* Closing all your browser windows and opening a new one
* Possibly clearing cache and cookies.
* Not going to AdWords via a book mark - but by opening a new browser window and getting to the login page by typing in the URL
* Trying a different browser.
* Updating your current browser to the most recent version if you are using an older version.
* Trying a different computer if you have one available to you.