diff --git a/gulliver/system/class.form.php b/gulliver/system/class.form.php
index d11e493fc..a8150de12 100755
--- a/gulliver/system/class.form.php
+++ b/gulliver/system/class.form.php
@@ -61,19 +61,43 @@ class Form extends XmlForm
      * @access public
      * @return string
      */
+
     public function setDefaultValues ()
     {
         foreach ($this->fields as $name => $content) {
             if (is_object( $content ) && get_class( $content ) != '__PHP_Incomplete_Class') {
                 if (isset( $content->defaultValue )) {
-                    $this->values[$name] = $content->defaultValue;
+                    switch ($content->type) {
+                        case "checkgroup":
+                        case "listbox":
+                            $defaultValueAux = trim($content->defaultValue);
+
+                            if ($defaultValueAux != "") {
+                                $this->values[$name] = $content->defaultValue;
+                            } else {
+                                $this->values[$name] = "__NULL__";
+                            }
+                            break;
+                        default:
+                            $this->values[$name] = $content->defaultValue;
+                            break;
+                    }
                 } else {
-                    $this->values[$name] = '';
+                    switch ($content->type) {
+                        case "checkgroup":
+                        case "listbox":
+                            $this->values[$name] = "__NULL__";
+                            break;
+                        default:
+                            $this->values[$name] = "";
+                            break;
+                    }
                 }
             } else {
                 $this->values[$name] = '';
             }
         }
+
         foreach ($this->fields as $k => $v) {
             if (is_object( $v )) {
                 //julichu
@@ -117,6 +141,7 @@ class Form extends XmlForm
             trigger_error( 'Faild to create cache file "' . $xmlform->parsedFile . '".', E_USER_ERROR );
         }
         $this->setDefaultValues();
+
         //to do: review if you can use the same form twice. in order to use once or not.
         //DONE: Use require to be able to use the same xmlform more than once.
         foreach ($this->fields as $k => $v) {
@@ -229,6 +254,7 @@ class Form extends XmlForm
         if (! is_array( $newValues )) {
             return;
         }
+
         foreach ($this->fields as $k => $v) {
             if (array_key_exists( $k, $newValues )) {
                 if (is_array( $newValues[$k] )) {
@@ -362,9 +388,9 @@ class Form extends XmlForm
                                     $values[$k] = $values[$k . "_label"] = null;
                                     foreach ($newValues[$k] as $i => $value) {
                                         //if $value is empty continue with the next loop, because this is a not selected/checked item
-                                        if (trim( $value ) == '') {
-                                            continue;
-                                        }
+                                        //if (trim( $value ) == '') {
+                                        //    continue;
+                                        //}
 
                                         $values[$k] .= (($i != 0) ? "|" : null) . $value;
 
@@ -510,8 +536,13 @@ class Form extends XmlForm
                                 }
                         }
                     } else {
-                        if ($v->type == 'checkgroup') {
-                            $values[$k] = null;
+                        switch ($v->type) {
+                            case "checkgroup":
+                            case "listbox":
+                                //This value is added when the user does not mark any checkbox
+                                $values[$k . "_label"] = "__NULL__";
+                                $values[$k] = "__NULL__";
+                                break;
                         }
                     }
                 } else {
diff --git a/gulliver/system/class.xmlform.php b/gulliver/system/class.xmlform.php
index be26b67e0..c399a06a0 100755
--- a/gulliver/system/class.xmlform.php
+++ b/gulliver/system/class.xmlform.php
@@ -3599,6 +3599,15 @@ class XmlForm_Field_Listbox extends XmlForm_Field
         if (! is_array( $value )) {
             $value = explode( '|', $value );
         }
+
+        $arrayAux = array();
+
+        foreach ($value as $index2 => $value2) {
+            $arrayAux[] = $value2 . "";
+        }
+
+        $value = $arrayAux;
+
         if ($this->mode === 'edit') {
             $itemWidth = '';
             if ($this->width != '') {
@@ -3606,10 +3615,10 @@ class XmlForm_Field_Listbox extends XmlForm_Field
             }
             $html = '<select multiple="multiple" id="form[' . $this->name . ']" name="form[' . $this->name . '][]" size="' . $this->size . '" ' . $itemWidth . '  ' . $this->NSFieldType() . '>';
             foreach ($this->option as $optionName => $option) {
-                $html .= '<option value="' . $optionName . '" ' . ((in_array( $optionName, $value )) ? 'selected' : '') . '>' . $option . '</option>';
+                $html .= "<option value=\"" . $optionName . "\" " . ((in_array( $optionName . "", $value )) ? "selected=\"selected\"" : "") . ">" . $option . "</option>";
             }
             foreach ($this->sqlOption as $optionName => $option) {
-                $html .= '<option value="' . $optionName . '" ' . ((in_array( $optionName, $value )) ? 'selected' : '') . '>' . $option . '</option>';
+                $html .= "<option value=\"" . $optionName . " \" " . ((in_array( $optionName . "", $value )) ? "selected=\"selected\" " : "") . ">" . $option . "</option>";
             }
             $html .= '</select>';
 
@@ -3618,17 +3627,17 @@ class XmlForm_Field_Listbox extends XmlForm_Field
         } elseif ($this->mode === 'view') {
             $html = '<select multiple="multiple" id="form[' . $this->name . ']" name="form[' . $this->name . '][]" size="' . $this->size . '" ' . $this->NSFieldType() . ' style="background: none;" disabled="disabled">';
             foreach ($this->option as $optionName => $option) {
-                $html .= '<option value="' . $optionName . '" ' . ((in_array( $optionName, $value )) ? 'class="module_ListBoxView" selected="selected"' : '') . '>' . $option . '</option>';
+                $html .= "<option value=\"" . $optionName . " \" " . ((in_array( $optionName . "", $value )) ? "class=\"module_ListBoxView\" selected=\"selected\"" : "") . ">" . $option . "</option>";
             }
             foreach ($this->sqlOption as $optionName => $option) {
-                $html .= '<option value="' . $optionName . '" ' . ((in_array( $optionName, $value )) ? 'class="module_ListBoxView" selected="selected"' : '') . '>' . $option . '</option>';
+                $html .= "<option value=\"" . $optionName . " \" " . ((in_array( $optionName . "", $value )) ? "class=\"module_ListBoxView\" selected=\"selected\"" : "") . ">" . $option . "</option>";
             }
             $html .= '</select>';
             foreach ($this->option as $optionName => $option) {
-                $html .= '<input type="hidden" id="form[' . $this->name . ']" name="form[' . $this->name . '][]" value="' . ((in_array( $optionName, $value )) ? $optionName : '') . '">';
+                $html .= "<input type=\"hidden\" id=\"form[" . $this->name . "]\" name=\"form[" . $this->name . "][]\" value=\"" . ((in_array( $optionName . "", $value )) ? $optionName : "__NULL__") . "\">";
             }
             foreach ($this->sqlOption as $optionName => $option) {
-                $html .= '<input type="hidden" id="form[' . $this->name . ']" name="form[' . $this->name . '][]" value="' . ((in_array( $optionName, $value )) ? $optionName : '') . '">';
+                $html .= "<input type=\"hidden\" id=\"form[" . $this->name . "]\" name=\"form[" . $this->name . "][]\" value=\"" . ((in_array( $optionName . "", $value )) ? $optionName : "__NULL__") . "\">";
             }
             return $html;
         } else {
@@ -3802,20 +3811,20 @@ class XmlForm_Field_CheckGroup extends XmlForm_Field
         if (! is_array( $value )) {
             $value = explode( '|', $value );
         }
+
+        $arrayAux = array();
+
+        foreach ($value as $index2 => $value2) {
+            $arrayAux[] = $value2 . "";
+        }
+
+        $value = $arrayAux;
+
         if ($this->mode === 'edit') {
             $i = 0;
             $html = '';
             foreach ($this->options as $optionName => $option) {
-                $swCheked = 0;
-
-                foreach ($value as $index2 => $value2) {
-                    if (strlen($value2 . "") > 0 && $value2 == $optionName) {
-                          $swCheked = 1;
-                          break;
-                    }
-                }
-
-                $html = $html . "<input type=\"checkbox\" id=\"form[" . $this->name . "][" . $optionName . "]\" name=\"form[" . $this->name . "][]\" value=\"" . $optionName . "\"" . (($swCheked == 1) ? " checked=\"checked\" " : "") . "><span class=\"FormCheck\"><label for=\"form[" . $this->name . "][" . $optionName . "]\">" . $option . "</label></span></input>";
+                $html .= "<input type=\"checkbox\" id=\"form[" . $this->name . "][" . $optionName . "]\" name=\"form[" . $this->name . "][]\"  value=\"" . $optionName . "\"" . (in_array( $optionName . "", $value ) ? "checked = \"checked\" " : "") . "><span class=\"FormCheck\"><label for=\"form[" . $this->name . "][" . $optionName . "]\">" . $option . "</label></span></input>";
 
                 if (++ $i == count( $this->options )) {
                     $html .= '&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;' . $this->renderHint();
@@ -3826,17 +3835,8 @@ class XmlForm_Field_CheckGroup extends XmlForm_Field
         } elseif ($this->mode === 'view') {
             $html = '';
             foreach ($this->options as $optionName => $option) {
-                $swCheked = 0;
-
-                foreach ($value as $index2 => $value2) {
-                    if (strlen($value2 . "") > 0 && $value2 == $optionName) {
-                          $swCheked = 1;
-                          break;
-                    }
-                }
-
-                $html = $html . "<input class=\"FormCheck\" type=\"checkbox\" id=\"form[" . $this->name . "][" . $optionName . "]\" value=\"" . $optionName . "\"" . (($swCheked == 1) ? " checked=\"checked\" " : "") . " disabled=\"disabled\"><span class=\"FormCheck\"><label for=\"form[" . $this->name . "][" . $optionName . "]\">" . $option . "</label></span></input><br />";
-                $html = $html . "<input type=\"hidden\" name=\"form[" . $this->name . "][]\"  value=\"" . (($swCheked == 1) ? $optionName : "") . "\">";
+                $html .= "<input class=\"FormCheck\" type=\"checkbox\" id=\"form[" . $this->name . "][" . $optionName . "]\" value=\"" . $optionName . "\"" . (in_array( $optionName . "", $value ) ? " checked=\"checked\" " : "") . " disabled=\"disabled\"><span class=\"FormCheck\"><label for=\"form[" . $this->name . "][" . $optionName . "]\">" . $option . "</label></span></input><br />";
+                $html .= "<input type=\"hidden\" name=\"form[" . $this->name . "][]\"  value=\"" . ((in_array( $optionName . "", $value )) ? $optionName : "__NULL__") . "\">";
             }
             return $html;
         } else {