diff --git a/lang/en/vpl.php b/lang/en/vpl.php
index a23c695fddbd86fcaa514fe50634f70198882ebc..9a93fdd42d7077fb7f695f70e4d321bcd175e231 100644
--- a/lang/en/vpl.php
+++ b/lang/en/vpl.php
@@ -112,6 +112,7 @@ $string ['finalreduction_help'] = '<b>FR [NE/FE R]</b><br>
 <b>R</b> Grade reduction by evaluation. If it is a percent, it is apply over previous result.<br>';
 $string ['find'] = "Find";
 $string ['find_replace'] = 'Find/Replace';
+$string ['forceload'] = 'Force load';
 $string ['freeevaluations'] = 'Free evaluations';
 $string ['freeevaluations_help'] = 'Number of automatic evaluations that do not reduce final score';
 $string ['fulldescription'] = 'Full description';
diff --git a/views/vpl_grapher.class.php b/views/vpl_grapher.class.php
index d5a5c35660ff21bcd72cab31b6e3b637d22dff0a..6429780e2f4504dfe62586c1ee44bdebdf951bda 100644
--- a/views/vpl_grapher.class.php
+++ b/views/vpl_grapher.class.php
@@ -151,6 +151,11 @@ class vpl_grapher {
             $totalseries = array();
             if ($diff) {
                 $reqfiles = $this->vpl->get_fgm('required')->getAllFiles();
+                if (optional_param('forcegraphload', false, PARAM_INT)) {
+                    $timelimit = 0;
+                } else {
+                    $timelimit = 500;
+                }
             }
             foreach ($submissionslist as $subinstance) {
                 $submission = new mod_vpl_submission( $this->vpl, $subinstance );
@@ -162,7 +167,7 @@ class vpl_grapher {
                         $series[$name] = array_fill(0, $i - 1, null);
                     }
                     if ($diff && isset($reqfiles[$name])) {
-                        $value = vpl_diff::compute_filediff($reqfiles[$name], $data, 500);
+                        $value = vpl_diff::compute_filediff($reqfiles[$name], $data, $timelimit);
                     } else {
                         $value = strlen( $data );
                     }
@@ -184,9 +189,11 @@ class vpl_grapher {
             }
             self::draw( $title, get_string( 'submissions', VPL ) , get_string( "sizeb" ), $subsn, $series, $names );
         } catch (Exception $e) {
+            global $PAGE;
             echo '<span class="chart-area nograph">';
             echo '<b>' . $title . '</b><br>';
-            echo get_string('graphcomputationfailed', VPL);
+            echo get_string('graphcomputationfailed', VPL) . '<br>';
+            echo '<a href="'. $PAGE->url->out(true, array('forcegraphload' => 1)) .'">' . get_string('forceload', VPL) . '</a>';
             echo '</span>';
         }
     }