diff --git a/views/bootstrap/class.Bootstrap.php b/views/bootstrap/class.Bootstrap.php
index 7d7f4408d..017e213a1 100644
--- a/views/bootstrap/class.Bootstrap.php
+++ b/views/bootstrap/class.Bootstrap.php
@@ -1966,6 +1966,15 @@ $(document).ready(function() {
 		echo self::getAttributeEditField($attrdef, $attribute, $fieldname, $norequire, $namepostfix, $alwaysmultiple);
 	} /* }}} */
 
+	/**
+	 * Return html code for an input/select field of an attribute
+	 *
+	 * The passed attribute ($attribute) can either be an object of type
+	 * SeedDMS_Core_Attribute, scalar or an array. A scalar or array is
+	 * passed when the method is called to create the search form. In that
+	 * case $attribute has the value from the post data after submitting the
+	 * search form.
+	 */
 	function getAttributeEditField($attrdef, $attribute, $fieldname='attributes', $norequire=false, $namepostfix='', $alwaysmultiple=false) { /* {{{ */
 		$dms = $this->params['dms'];
 		$attr_id = $fieldname.'_'.$attrdef->getId().($namepostfix ? '_'.$namepostfix : '');
@@ -2002,10 +2011,19 @@ $(document).ready(function() {
 			$content .= $this->getDocumentChooserHtml("attr".$attrdef->getId(), $target, $attr_name);
 			break;
 		case SeedDMS_Core_AttributeDefinition::type_user:
-			$target = $attribute ? $attribute->getValueAsArray() : [];
 			$objvalue = [];
-			foreach($target as $t)
-				$objvalue[] = $t->getId();
+			if($attribute) {
+				if(is_object($attribute)) {
+					$target = $attribute->getValueAsArray();
+					foreach($target as $t)
+						$objvalue[] = $t->getId();
+				} elseif(is_array($attribute)) {
+					foreach($attribute as $t)
+						$objvalue[] = $t;
+				} else {
+					$objvalue[] = $attribute;
+				}
+			}
 			$users = $dms->getAllUsers();
 			if($users) {
 				$allowempty = $attrdef->getMinValues() == 0;
@@ -2025,10 +2043,19 @@ $(document).ready(function() {
 			}
 			break;
 		case SeedDMS_Core_AttributeDefinition::type_group:
-			$target = $attribute ? $attribute->getValueAsArray() : [];
 			$objvalue = [];
-			foreach($target as $t)
-				$objvalue[] = $t->getId();
+			if($attribute) {
+				if(is_object($attribute)) {
+					$target = $attribute->getValueAsArray();
+					foreach($target as $t)
+						$objvalue[] = $t->getId();
+				} elseif(is_array($attribute)) {
+					foreach($attribute as $t)
+						$objvalue[] = $t;
+				} else {
+					$objvalue[] = $attribute;
+				}
+			}
 			$groups = $dms->getAllGroups();
 			if($groups) {
 				$allowempty = $attrdef->getMinValues() == 0;
diff --git a/views/bootstrap4/class.Bootstrap4.php b/views/bootstrap4/class.Bootstrap4.php
index 93ffc29f2..9e7c2fa64 100644
--- a/views/bootstrap4/class.Bootstrap4.php
+++ b/views/bootstrap4/class.Bootstrap4.php
@@ -1985,6 +1985,15 @@ $(document).ready(function() {
 		echo self::getAttributeEditField($attrdef, $attribute, $fieldname, $norequire, $namepostfix, $alwaysmultiple);
 	} /* }}} */
 
+	/**
+	 * Return html code for an input/select field of an attribute
+	 *
+	 * The passed attribute ($attribute) can either be an object of type
+	 * SeedDMS_Core_Attribute, scalar or an array. A scalar or array is
+	 * passed when the method is called to create the search form. In that
+	 * case $attribute has the value from the post data after submitting the
+	 * search form.
+	 */
 	function getAttributeEditField($attrdef, $attribute, $fieldname='attributes', $norequire=false, $namepostfix='', $alwaysmultiple=false) { /* {{{ */
 		$dms = $this->params['dms'];
 		$attr_id = $fieldname.'_'.$attrdef->getId().($namepostfix ? '_'.$namepostfix : '');
@@ -2018,18 +2027,27 @@ $(document).ready(function() {
 			$content .= "<input type=\"text\" class=\"form-control\" id=\"".$attr_id."\" name=\"".$attr_name."\" value=\"".htmlspecialchars($objvalue)."\"".((!$norequire && $attrdef->getMinValues() > 0) ? ' required="required"' : '')." data-rule-number=\"true\"/>";
 			break; */
 		case SeedDMS_Core_AttributeDefinition::type_folder:
-			$target = $attribute ? $attribute->getValue() : null;
+			$target = $attribute ? (is_object($attribute) ? $attribute->getValue() : $attribute) : null;
 			$content .= $this->getFolderChooserHtml("attr".$attrdef->getId(), M_READWRITE, -1, $target, $attr_name, false);
 			break;
 		case SeedDMS_Core_AttributeDefinition::type_document:
-			$target = $attribute ? $attribute->getValue() : null;
+			$target = $attribute ? (is_object($attribute) ? $attribute->getValue() : $attribute) : null;
 			$content .= $this->getDocumentChooserHtml("attr".$attrdef->getId(), $target, $attr_name);
 			break;
 		case SeedDMS_Core_AttributeDefinition::type_user:
-			$target = $attribute ? $attribute->getValueAsArray() : [];
 			$objvalue = [];
-			foreach($target as $t)
-				$objvalue[] = $t->getId();
+			if($attribute) {
+				if(is_object($attribute)) {
+					$target = $attribute->getValueAsArray();
+					foreach($target as $t)
+						$objvalue[] = $t->getId();
+				} elseif(is_array($attribute)) {
+					foreach($attribute as $t)
+						$objvalue[] = $t;
+				} else {
+					$objvalue[] = $attribute;
+				}
+			}
 			$users = $dms->getAllUsers();
 			if($users) {
 				$allowempty = $attrdef->getMinValues() == 0;
@@ -2049,10 +2067,19 @@ $(document).ready(function() {
 			}
 			break;
 		case SeedDMS_Core_AttributeDefinition::type_group:
-			$target = $attribute ? $attribute->getValueAsArray() : [];
 			$objvalue = [];
-			foreach($target as $t)
-				$objvalue[] = $t->getId();
+			if($attribute) {
+				if(is_object($attribute)) {
+					$target = $attribute->getValueAsArray();
+					foreach($target as $t)
+						$objvalue[] = $t->getId();
+				} elseif(is_array($attribute)) {
+					foreach($attribute as $t)
+						$objvalue[] = $t;
+				} else {
+					$objvalue[] = $attribute;
+				}
+			}
 			$groups = $dms->getAllGroups();
 			if($groups) {
 				$allowempty = $attrdef->getMinValues() == 0;