Index: views_content/plugins/views/views_content_plugin_display_ctools_context.inc
===================================================================
--- views_content/plugins/views/views_content_plugin_display_ctools_context.inc  (revision 1282)
+++ views_content/plugins/views/views_content_plugin_display_ctools_context.inc  (working copy)
@@ -70,6 +70,15 @@
 
       if (isset($info['preprocess functions']) && is_array($info['preprocess functions'])) {
         foreach ($info['preprocess functions'] as $preprocess_function) {
+          // If function doesn't not exist yet, include all related files.
+          if (!function_exists($preprocess_function)) {
+            if (!empty($info['include files']) && is_array($info['include files'])) {
+              foreach ($info['include files'] as $file) {
+                @include_once($file);
+              }
+            }
+          }
+          // Probably this further existance check is redundant.
           if (function_exists($preprocess_function)) {
             $preprocess_function($this->variables, $this->definition['theme']);
           }