I tried using the combobox for a query form. It bails out with

Warning: call_user_func_array() expects parameter 1 to be a valid callback, class 'SFComboBoxInput' not found in C:\xampplite\htdocs\w\extensions\SemanticForms\includes\SF_FormPrinter.php on line 1312

Instead of the expected combobox, the field definition is displayed, e.g.

{{{field|foo|input type=combobox|autocomplete on concept=bar}}}

MW 1.16.0
SF 2.0
SFI 0.3.1

Version: unspecified
Severity: normal