AjaxDropdownPreloader control allows to have a pair of dependent fields on a page. Usually dependent field is a dropdown.
For example groups dropdown (master) and users dropdown (dependent). In such case on each "groups dropdown" change an "users dropdown" is revised to contains only records, associated with that group.
I recently discovered however, that in case of dependent field has multiple attribute (e.g. <select name="test" multiple>...</select>), then JavaScript error is shown instead of record revising.
Related Tasks
Error rendering macro 'jira' : Unable to locate Jira server for this macro. It may be due to Application Link configuration.