change system default display order

src/mobile-main.js

@@ -214,7 +214,7 @@ Vue.prototype.$locale = {
             moment.tz.setDefault();
         }
     },
-    getAllTimezones: function () {
+    getAllTimezones: function (includeSystemDefault) {
         const allTimezones = timezone.all;
         const allTimezoneInfos = [];
 
@@ -226,6 +226,14 @@ Vue.prototype.$locale = {
             });
         }
 
+        if (includeSystemDefault) {
+            allTimezoneInfos.push({
+                name: '',
+                utcOffset: this.defaultTimezoneOffset,
+                displayName: i18n.t('System Default')
+            });
+        }
+
         allTimezoneInfos.sort(function(c1, c2){
             const utcOffset1 = parseInt(c1.utcOffset.replace(':', ''));
             const utcOffset2 = parseInt(c2.utcOffset.replace(':', ''));

src/views/mobile/Settings.vue

@@ -37,7 +37,6 @@
                         :title="$t('Timezone')"
                         smart-select :smart-select-params="{ openIn: 'popup', searchbar: true, searchbarPlaceholder: $t('Timezone'), searchbarDisableText: $t('Cancel'), closeOnSelect: true, popupCloseLinkText: $t('Done'), scrollToSelectedItem: true }">
                         <select v-model="currentTimezone">
-                            <option value="">{{ `(UTC${defaultTimezoneOffset}) ${$t('System Default')}` }}</option>
                             <option v-for="timezone in allTimezones"
                                     :key="timezone.name"
                                     :value="timezone.name">{{ `(UTC${timezone.utcOffset}) ${timezone.displayName}` }}</option>
@@ -117,10 +116,7 @@ export default {
             return this.$locale.getAllLanguages();
         },
         allTimezones() {
-            return this.$locale.getAllTimezones();
-        },
-        defaultTimezoneOffset() {
-            return this.$locale.defaultTimezoneOffset;
+            return this.$locale.getAllTimezones(true);
         },
         currentLocale: {
             get: function () {