[FIX] In the case of filtering by categories by using the {input} or {select} filters it was not filtering. It only worked when using the {categories} filter.

When using the Customsearch wiki-plugin, when setting up a filter that uses {input} or {select} it fails to work. In the case of filtering by categories by using the {input} or {select} filters it was not filtering. It only worked when using the {categories} filter. For example:

{categories _parent="1" _style="select" class="form-control" _firstlabel="All Skill Levels"} works perfectly fine. However, if we need more fine grained control, e.g. on labels or the order in which the categories show, or the layout etc... we need to use {input} or {select}, e.g. {select _filter="categories" _options="2,3,4" _labels="Beginner,Intermediate,Advanced" class="form-control" _firstlabel="All Skill Levels"} fails without the included fix.