diff --git a/NEWS b/NEWS
index 5fba47add..078e42694 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,7 @@ Bug fixes
  - [web] fixed condition of copy action on cards
  - [web] fixed display of notification email in calendar properties
  - [web] fixed display of multi-days events when some weekdays are disabled
+ - [web] fixed synchronisation of calendar categories
 
 4.0.2 (2018-08-24)
 ------------------
diff --git a/UI/Templates/PreferencesUI/UIxPreferences.wox b/UI/Templates/PreferencesUI/UIxPreferences.wox
index b5b67043b..5a9742a02 100644
--- a/UI/Templates/PreferencesUI/UIxPreferences.wox
+++ b/UI/Templates/PreferencesUI/UIxPreferences.wox
@@ -409,7 +409,7 @@
                               ng-repeat="item in
                                          app.preferences.defaults.SOGoCalendarCategories
                                          track by $index">
-                  <sg-color-picker ng-model="app.preferences.defaults.SOGoCalendarCategoriesColors[item]"><!-- color picker--></sg-color-picker>
+                  <sg-color-picker ng-model="app.preferences.defaults.SOGoCalendarCategoriesColorsValues[$index]"><!-- color picker--></sg-color-picker>
                   <md-input-container class="md-block md-flex">
 	            <input type="text" label:aria-label="Calendar Category" required="required"
                            name="calendarCategory_{{$index}}"
diff --git a/UI/WebServerResources/js/Preferences/Preferences.service.js b/UI/WebServerResources/js/Preferences/Preferences.service.js
index a912ae4c3..e161dc857 100644
--- a/UI/WebServerResources/js/Preferences/Preferences.service.js
+++ b/UI/WebServerResources/js/Preferences/Preferences.service.js
@@ -114,10 +114,13 @@
           angular.isArray(data.Forward.forwardAddress))
         data.Forward.forwardAddress = data.Forward.forwardAddress.join(",");
 
-      if (angular.isUndefined(data.SOGoCalendarCategoriesColors)) {
-        data.SOGoCalendarCategoriesColors = {};
+      // Split calendar categories colors keys and values
+      if (angular.isUndefined(data.SOGoCalendarCategories))
         data.SOGoCalendarCategories = [];
-      }
+      data.SOGoCalendarCategoriesColorsValues = [];
+      _.forEach(data.SOGoCalendarCategories, function (value) {
+        data.SOGoCalendarCategoriesColorsValues.push(data.SOGoCalendarCategoriesColors[value]);
+      });
 
       if (angular.isUndefined(data.SOGoContactsCategories))
         data.SOGoContactsCategories = [];
@@ -329,6 +332,13 @@
     if (preferences.defaults.Forward && preferences.defaults.Forward.forwardAddress)
       preferences.defaults.Forward.forwardAddress = preferences.defaults.Forward.forwardAddress.split(",");
 
+    // Merge back calendar categories colors keys and values
+    preferences.defaults.SOGoCalendarCategoriesColors = {};
+    _.forEach(preferences.defaults.SOGoCalendarCategories, function(key, i) {
+      preferences.defaults.SOGoCalendarCategoriesColors[key] = preferences.defaults.SOGoCalendarCategoriesColorsValues[i];
+    });
+    delete preferences.defaults.SOGoCalendarCategoriesColorsValues;
+
     if (preferences.settings.Calendar && preferences.settings.Calendar.PreventInvitationsWhitelist) {
       _.forEach(preferences.settings.Calendar.PreventInvitationsWhitelist, function(user) {
         whitelist[user.uid] = user.$shortFormat();
diff --git a/UI/WebServerResources/js/Preferences/PreferencesController.js b/UI/WebServerResources/js/Preferences/PreferencesController.js
index f5df6eaad..9d0a44568 100644
--- a/UI/WebServerResources/js/Preferences/PreferencesController.js
+++ b/UI/WebServerResources/js/Preferences/PreferencesController.js
@@ -64,13 +64,13 @@
 
     this.resetCalendarCategories = function(form) {
       this.preferences.defaults.SOGoCalendarCategories = _.keys($window.defaultCalendarCategories);
-      this.preferences.defaults.SOGoCalendarCategoriesColors = angular.copy($window.defaultCalendarCategories);
+      this.preferences.defaults.SOGoCalendarCategoriesColorsValues = _.values($window.defaultCalendarCategories);
       form.$setDirty();
     };
 
     this.addCalendarCategory = function(form) {
-      this.preferences.defaults.SOGoCalendarCategoriesColors[l('New category')] = "#aaa";
       this.preferences.defaults.SOGoCalendarCategories.push(l('New category'));
+      this.preferences.defaults.SOGoCalendarCategoriesColorsValues.push("#aaa");
       focus('calendarCategory_' + (this.preferences.defaults.SOGoCalendarCategories.length - 1));
       form.$setDirty();
     };
@@ -80,9 +80,8 @@
     };
 
     this.removeCalendarCategory = function(index, form) {
-      var key = this.preferences.defaults.SOGoCalendarCategories[index];
       this.preferences.defaults.SOGoCalendarCategories.splice(index, 1);
-      delete this.preferences.defaults.SOGoCalendarCategoriesColors[key];
+      this.preferences.defaults.SOGoCalendarCategoriesColorsValues.splice(index, 1);
       form.$setDirty();
     };