TypeError with invalid Ext.query('#id.class:input')

[shanimal]

The result that occurs instead:

• TypeError: Cannot read property '0' of null

Test Case:

    Ext.query('#id.class:input')

HELPFUL INFORMATION
Operating System:

• Mac v10.8.2 b12C60

Browser:

• Google Chrome 24.0.1312.56

Site:

• http://www.sencha.com/ (screenshot)

Note I expected the selector to be empty, but it threw an error. This doesn't happen in jQuery, is this normal/acceptable behavior for extjs?