Version 1.7.. Well, it sure has been long enough coming (okay, I've been working a lot on my C++ "game engine" lately...)
Mainly fixed in this release is the multiline comments. I've spent some time looking at the CppColorer class (the VS built-in C++ colorer), and how it handles multiline comments, and rebuilt the HLSLHighlighterr completely to work in a similar way. The CppColorer class also has a handy public method which I'm now calling in the main Highlighterr routine to find the comment status at the start of a line. I have tested it fairly thoroughly, and haven't managed to confuse it yet!
To install the extension, download the and then double-click on the Highlighterr.vsix file. This should bring up a dialog saying something about which version of Visual Studio it's going on. Only Visual Studio 2010 should be in the list.
Once installed, the code highlighting will be active. You can change the colours that are used via the Tools > Options > Environment > Fonts and Colors options screen.
Note that Visual Studio will have to be restarted a couple of times for the extension to start working, maybe someone knows how to fix this issue.
You can uninstall it via Tools > Extension Manager in Visual Studio.
Uninstall previous versions before installing a new version, or I think VS will tell you the same.
Requires Visual Studio 2010 to be installed on the current machine.
If you have any problems with it, please post a comment here somewhere and I'll be sure to look into it.