diff --git a/application/forms.class.inc.php b/application/forms.class.inc.php
index eadd1661b..a28d5154c 100644
--- a/application/forms.class.inc.php
+++ b/application/forms.class.inc.php
@@ -1223,7 +1223,7 @@ class DesignerComboField extends DesignerFormField
 		$sChecked = $this->defaultValue ? 'checked' : '';
 		$sMandatory = $this->bMandatory ? 'true' :  'false';
 		$sReadOnly = $this->IsReadOnly() ? 'disabled="disabled"' :  '';
-		if ($this->IsSorted())
+		if ($this->IsSorted() && isset($this->aAllowedValues) )
 		{
 			asort($this->aAllowedValues);
 		}
@@ -1271,19 +1271,17 @@ class DesignerComboField extends DesignerFormField
 					$sHtml .= "<option value=\"\">".$this->sNullLabel."</option>";
 				}
 			}
-			foreach($this->aAllowedValues as $sKey => $sDisplayValue)
-			{
-				if ($this->bMultipleSelection)
-				{
-					$sSelected = in_array($sKey, $this->defaultValue) ? 'selected' : '';
+			if ( isset($this->aAllowedValues) ) {
+				foreach ($this->aAllowedValues as $sKey => $sDisplayValue) {
+					if ($this->bMultipleSelection) {
+						$sSelected = in_array($sKey, $this->defaultValue) ? 'selected' : '';
+					} else {
+						$sSelected = ($sKey == $this->defaultValue) ? 'selected' : '';
+					}
+					// Quick and dirty: display the menu parents as a tree
+					$sHtmlValue = str_replace(' ', '&nbsp;', $sDisplayValue);
+					$sHtml .= "<option value=\"".htmlentities($sKey, ENT_QUOTES, 'UTF-8')."\" $sSelected>$sHtmlValue</option>";
 				}
-				else
-				{
-					$sSelected = ($sKey == $this->defaultValue) ? 'selected' : '';
-				}
-				// Quick and dirty: display the menu parents as a tree
-				$sHtmlValue = str_replace(' ', '&nbsp;', htmlentities($sDisplayValue, ENT_QUOTES, 'UTF-8'));
-				$sHtml .= "<option value=\"".htmlentities($sKey, ENT_QUOTES, 'UTF-8')."\" $sSelected>$sHtmlValue</option>";
 			}
 			$sHtml .= "</select>";
 			if ($this->bOtherChoices)
diff --git a/pages/ajax.render.php b/pages/ajax.render.php
index 8df024513..fbe25a152 100644
--- a/pages/ajax.render.php
+++ b/pages/ajax.render.php
@@ -1368,7 +1368,16 @@ EOF
 				foreach($aUpdatedProperties as $sProp)
 				{
 					$sDecodedProp = str_replace('attr_', '', $sProp); // Remove the attr_ prefix
-					$aCurrentValues[$sDecodedProp] = (isset($aPreviousValues[$sProp]) ? $aPreviousValues[$sProp] : ''); // Set the previous value
+					// Set the previous value
+					if  ( isset($aPreviousValues[$sProp]) && $aPreviousValues[$sProp] != '' ){
+						$aCurrentValues[$sDecodedProp] = $aPreviousValues[$sProp];
+					} else {
+						if(gettype($aCurrentValues[$sDecodedProp]) == "array") {
+							$aCurrentValues[$sDecodedProp] = [];
+						} else {
+							$aCurrentValues[$sDecodedProp] = '';
+						}
+					}
 					$aUpdatedDecoded[] = $sDecodedProp;
 				}