Revert "filter: Fix filtering by list item properties"

This partially reverts commit bff191b6.
The hasSpecialSearch() method can be retired in `develop-next` — NOT in the
`develop` branch

include/class.forms.php

@@ -594,6 +594,17 @@ class FormField {
         return null;
     }
 
+    /**
+     * Indicates if the field provides for searching for something other
+     * than keywords. For instance, textbox fields can have hits by keyword
+     * searches alone, but selection fields should provide the option to
+     * match a specific value or set of values and therefore need to
+     * participate on any search builder.
+     */
+    function hasSpecialSearch() {
+        return true;
+    }
+
     function getConfigurationForm($source=null) {
         if (!$this->_cform) {
             $type = static::getFieldType($this->get('type'));
@@ -688,6 +699,10 @@ class TextboxField extends FormField {
         );
     }
 
+    function hasSpecialSearch() {
+        return false;
+    }
+
     function validateEntry($value) {
         parent::validateEntry($value);
         $config = $this->getConfiguration();
@@ -758,6 +773,10 @@ class TextareaField extends FormField {
         );
     }
 
+    function hasSpecialSearch() {
+        return false;
+    }
+
     function display($value) {
         $config = $this->getConfiguration();
         if ($config['html'])
@@ -810,6 +829,10 @@ class PhoneField extends FormField {
         );
     }
 
+    function hasSpecialSearch() {
+        return false;
+    }
+
     function validateEntry($value) {
         parent::validateEntry($value);
         $config = $this->getConfiguration();
@@ -1108,6 +1131,9 @@ class ThreadEntryField extends FormField {
     function isPresentationOnly() {
         return true;
     }
+    function hasSpecialSearch() {
+        return false;
+    }
 
     function getConfigurationOptions() {
         global $cfg;
@@ -1428,6 +1454,10 @@ class FileUploadField extends FormField {
         );
     }
 
+    function hasSpecialSearch() {
+        return false;
+    }
+
     /**
      * Called from the ajax handler for async uploads via web clients.
      */