Index: sources/storage/Settings.cpp
===================================================================
diff -u -r465a935949a85d3d1bebd11979737ff38ef96122 -r35db01154f90ebfdb6174033a66f5c20af82e14d
--- sources/storage/Settings.cpp	(.../Settings.cpp)	(revision 465a935949a85d3d1bebd11979737ff38ef96122)
+++ sources/storage/Settings.cpp	(.../Settings.cpp)	(revision 35db01154f90ebfdb6174033a66f5c20af82e14d)
@@ -88,28 +88,54 @@
     }
 
     for (const auto &detail : details) {
+        bool    enableDuplicateKey = false;
+        QString attribute = QString("%1%2").arg(_config_attribute_tag);
         QString group = "";
         QStringList lines = detail.content.split('\n');
         for (QString line : lines) {
-            // ignore empty lines
-            if ( line.trimmed().isEmpty() ) continue;
+            // ----- trim the line
+            line = line.trimmed();
 
-            // remove comments
+            // ----- ignore empty lines
+            if ( line.isEmpty() ) continue;
+
+            // ----- find comments
             int  commentPosition  = line.indexOf('#');
-            if ( commentPosition == 0 ) continue; // comment line
-            if ( commentPosition  > 0 )           // inline comment
-                line.truncate(commentPosition);
 
+
+            // ----- ignore comment line or find attributes
+            if ( commentPosition == 0 ) {
+
+                // ----- find the configuration file attribute
+                int  attributeTagPosition = line.indexOf(_config_attribute_tag);
+                if ( attributeTagPosition == 0 ) {
+
+                    // ----- find the attribute : duplicate_key_...
+                    if      ( line == attribute.arg( _duplicate_key_on ) ) { enableDuplicateKey = true  ;}
+                    else if ( line == attribute.arg(_duplicate_key_off ) ) { enableDuplicateKey = false ;}
+
+                    else    {
+                        LOG_EVENT_UI(( "Unknown '" + line + "' attribute in %1").arg(detail.category));
+                    }
+                }
+
+                // next line
+                continue;
+            }
+
+            // ----- remove inline comment
+            if ( commentPosition  > 0 ) line.truncate(commentPosition);
+
+            // ----- find group
             if (line.contains("[") && line.contains("]")) {
                 line.replace("[","").replace("]", "");
-                group = line.trimmed();
+                group = line;
             }
             else {
                 if ( group.isEmpty() ) {
                     continue;
                 }
                 else {
-                    line = line.trimmed();
                     if ( ! line.isEmpty() ) {
                         QString key   = "";
                         QString value = "";
@@ -121,7 +147,7 @@
                         else {
                             key     = line;
                         }
-                        _Settings.add(group, key, QVariant(value), detail.location, detail.category);
+                        _Settings.add(group, key, QVariant(value), detail.location, detail.category, enableDuplicateKey);
                         // DEBUG: qDebug() << group << key << value << location << category;
                     }
                 }
@@ -145,7 +171,11 @@
     //          << vValue;
     QString mFileName = fileName(vCategory);
     QString mContent;
-    _Settings.add(vGroup, vKey, vValue,"", vCategory);
+    // --------------------------------------------------------------------------------------------------------------
+    //Note: the configuration files which can be saved, are like settings and should not have duplicate values.
+    //      as an example the Alarm volume can't have two separate duplicate entry in the settings.
+    // --------------------------------------------------------------------------------------------------------------
+    _Settings.add(vGroup, vKey, vValue,"", vCategory, false);
     QString mPath = QFileInfo(mFileName).absolutePath();
     if ( mPath.trimmed().isEmpty() ) {
         LOG_DEBUG("The settings path is empty.");