Cannot open a text editor if the font used is "Proggy Opti Small" (http://www.proggyfonts.com/index.php?menu=download).
A null reference exception pops up without any further details after double clicking on a C# file icon in the Solution Explorer.
From analysing previous exceptions with a debugger, a few other exceptions thrown in System.Drawing.dll are masked by the NullReferenceException. (ArgumentException: Only TrueType fonts are supported. This is not a TrueType font.)
I'm marking this issue as blocking because the error is not detailed enough for the user.
Also, selecting a new font does not fix the issue right away. A complete restart of visual studio is mandatory.
If non TrueType fonts are not supported, they should not be displayed as a choice in the font selector.
A memory dump is available if necessary.