It is installed in Program Files\Waterfox Limited\Waterfox and it is re-set as the default browser. I also did the following:
-Made IE9 as the default browser, the htm/html icons changed properly to IE icons. Then I opened Waterfox 16.0.1, I was greeted with the 'make default' window, clicked ok but icons remained white. They open with Waterfox but do not display the Waterfox icon.
-Uninstalled Waterfox 16.0.1, installed Waterfox 15, htm/html icons are now showing as they should, ie the waterfox logo
-Uninstalled Warerfox 15, installed again Waterfox 16.0.1, same problem, no waterfox icon image for htm. They open with Waterfox but do not display the Waterfox icon.
-Cleaned Icon Cache, restarted PC, no luck.
-Used CCleaner to check for references to the old installation path (C:\Program Files\Waterfox) but didn't find any
-CCleaner showed two more registry keys associated with Edit and Print of HTML, but they both reference something that doesn't exist in my PC and if I remember well, it is relating to Microsoft Office. Mind you, I never installed MS Office in my PC at home, I use AOO... (I will post the keys later when I get back home).
As I see it, just the fact that reverting back to WF15 solves the problem, it shows that something is missing from the registry in WF16.0.1. Also, the references to Program Files (x86) in Registry should not be there. I fixed all of them myself (I think) but still no icons. And since I am currently working on web projects, not being able to see the icons is a pain in the bum.
Can people here test this and give some feedback if they have the same issue? Just create a blank text document, rename it to myfile.html or htm and see if it displays the icon.