diff --git a/src/core/PasswordGenerator.cpp b/src/core/PasswordGenerator.cpp
index 01641bc802..aa0f3e7172 100644
--- a/src/core/PasswordGenerator.cpp
+++ b/src/core/PasswordGenerator.cpp
@@ -261,8 +261,10 @@ QVector<PasswordGroup> PasswordGenerator::passwordGroups() const
     if (!m_custom.isEmpty()) {
         PasswordGroup group;
 
-        for (auto ch : m_custom) {
-            group.append(ch);
+        for (const auto& ch : m_custom) {
+            if (!group.contains(ch)) {
+                group.append(ch);
+            }
         }
 
         passwordGroups.append(group);