Index: core/units/user_groups/user_groups_eh.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- core/units/user_groups/user_groups_eh.php	(revision 15997)
+++ core/units/user_groups/user_groups_eh.php	(revision )
@@ -105,10 +105,15 @@
 			$ids = $this->StoreSelectedIDs($event);
 
 			if ($ids) {
+				/** @var UsersItem $user */
 				$user = $this->Application->recallObject('u');
-				/* @var $user kDBItem */
 
-				$user->SetDBField('PrimaryGroupId', array_shift($ids));
+				$sql = 'SELECT GroupId
+						FROM ' . $this->Application->GetTempName(TABLE_PREFIX . 'UserGroupRelations', 'prefix:u') . '
+						WHERE Id = ' . array_shift($ids);
+				$group_id = $this->Conn->GetOne($sql);
+
+				$user->SetDBField('PrimaryGroupId', $group_id);
 				$user->Update();
 			}
 
@@ -159,4 +164,4 @@
 				}
 			}
 		}
-	}
\ No newline at end of file
+	}
Index: core/install/upgrades.sql
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- core/install/upgrades.sql	(revision 15999)
+++ core/install/upgrades.sql	(revision )
@@ -2993,6 +2993,7 @@
 ALTER TABLE CategoryItems ADD Id int(11) NOT NULL auto_increment FIRST, ADD PRIMARY KEY (Id);
 ALTER TABLE UserGroupRelations DROP PRIMARY KEY;
 ALTER TABLE UserGroupRelations ADD Id int(11) NOT NULL auto_increment FIRST, ADD PRIMARY KEY (Id), ADD UNIQUE KEY UserGroup (PortalUserId, GroupId);
+DELETE FROM UserPersistentSessionData WHERE VariableName IN ('u-ug[Default]columns_.', 'g-ug[Default]columns_.');
 ALTER TABLE SpamControl ADD Id int(11) NOT NULL auto_increment FIRST, ADD PRIMARY KEY (Id);
 
 INSERT INTO SystemSettings VALUES(DEFAULT, 'SSLDomain', '', 'In-Portal', 'in-portal:configure_advanced', 'la_section_SettingsSSL', 'la_config_SSLDomain', 'text', '', '', 30.01, 0, 1, NULL);