Why would Intellisense stop working?

Question

I added some members to an enum:

public enum SaveTypes
{
    MSAccess,
    CSV,
    XML,
    JSON,
    SQLite,
    MySQL,
    NoSQL
};

(the last two types are new).

I then added this code:

. . .
else if (st == HandheldServerGlobals.SaveTypes.SQLite)
{
    SaveToSQLite(invItem, dbContext);
}
else if (st == HandheldServerGlobals.SaveTypes.MySQL)
{
    SaveToSQLite(invItem, dbContext);
}
else if (st == HandheldServerGlobals.SaveTypes.NoSQL)
{
    SaveToSQLite(invItem, dbContext);
}

...but I had to add the "MySQL" and "NoSQL" by hand (carpal tunnel, here we come); IOW, mashing the "." key after "SaveTypes" did not invoke Intellisense. Thinking perhaps I needed to rebuild the project, and THEN it would recognize those new enum members, I did so - but still, Intellisense is not invoked. Why? I noticed that at home yesterday, too, that Intellisense had seemed to lose its senses. Two different machines, but both are running VS 2013 Ultimate. There was a recent VS update...is that the problem?