lost ability to select multiple objects

[MaxStudio]

I seem to have lost the ability to select multiple objects. The only way I can select them is if I completely encircle them. Holding shift doesn't work and intersecting while holding option does not work either.

Is there a keyboard shortcut I might have accidentally hit?

Thanks in advance

[Ray Libby]

Do a search of "+shift +key +not +working". Don't include the quotes, the plus signs will help narrow the search.