diff --git a/presentation/lookAndFeel/knowledgeTree/administration/usermanagement/listUsersBL.php b/presentation/lookAndFeel/knowledgeTree/administration/usermanagement/listUsersBL.php
index 5a0de10..6c4c939 100644
--- a/presentation/lookAndFeel/knowledgeTree/administration/usermanagement/listUsersBL.php
+++ b/presentation/lookAndFeel/knowledgeTree/administration/usermanagement/listUsersBL.php
@@ -37,6 +37,18 @@ require_once("$default->fileSystemRoot/presentation/lookAndFeel/knowledgeTree/ad
 
 if (checkSession()) {	
     $oPatternCustom = & new PatternCustom();
+    if (Permission::userIsUnitAdministrator() && !$fGroupID) {
+    	$default->log->info("unitadmin and undefined fGroupID");
+    	// #3519 select a group in your unit if you're a unit administrator and none has been selected
+	    $sql = $default->db;
+	    $sql->query("SELECT group_id FROM $default->groups_units_table WHERE unit_id = " . 
+	    		    User::getUnitID($_SESSION["userID"]) . " ORDER BY group_id");
+	    if ($sql->next_record()) {
+	        $fGroupID = $sql->f("group_id");
+	    }
+    } else {
+    	$default->log->info("fGroupID=$fGroupID");
+    }
     $oPatternCustom->setHtml(getPage($fGroupID));
 	require_once("$default->fileSystemRoot/presentation/webpageTemplate.inc");
 	$main->setCentralPayload($oPatternCustom);