Solution Explorer - search no longer shows items within source files

Windows 7, 64-bit.

VS2012 version 4.5.50709, R# 7.1.1

I'm working on two solutions.  Each has over 50 projects within.  In one of the solutions when I perform a search using the search facility within Solution Explorer, I can see relevant classes, enumerations etc within files.  In the other solution when I perform the same search, I can only see items down to the file level.

Here's an example.  I have a project named TelecomCore that is in both solutions and contains a C# file named Domain.cs.  Within the file there is the definition of an enumeration named "Domain".  If I search for Domain in one of the solutions I get this:

TelecomCore (project)

        Domain.cs (source file)

In the other solution I get this:

TelecomCore (project)

        Domain.cs (source file)

                 Domain (enumeration)

Why can I see the enumeration when I search in one solution and not the other? Is there a setting somewhere? I've tried deleting all of the temporary files associated with the solution to no avail.