Attached is a screen cap of what I'm talking about. The line of tabs across the top and the options down the side do not display. All modules are affected. The editor displays in custom html modules. This is happening on almost all my Joomla 3x sites, regardless of joomla version or template, or template source. The last time I can be sure I opened a module admin window was in August. Everything worked fine then. These sites are all on two host servers owned by the same company. I contacted the host and he suggested a permissions problem and made some changes. That did not affect the problem.

Everything is fine on the front end of all these sites so clients are not screaming - yet. On the admin side it's only the modules that aren't working properly.

The odd thing is that a joomla 3.6.4 installation I made today as a test works fine as does my most recent new site which went up May 2016. I also have a subdomain of a number of J51 demo sites, installed from your demo install zips along with some joomla installations from my cpanel that I made to test various components like shopping carts. These installations use various joomla 3x versions. Everything in that subdomain works fine.

I know this isn't a J51 template or extension issue but perhaps someone has some ideas that might help.

Thank you.