Set timeline scale on zoom automatically

app/assets/javascripts/angular/timelines/directives/timeline-toolbar-directive.js

@@ -61,9 +61,6 @@ angular.module('openproject.timelines.directives')
 
       scope.$watch('currentScaleName', function(newScaleName, oldScaleName){
         if (newScaleName !== oldScaleName) {
-          scope.currentScale = scope.timeline.ZOOM_CONFIGURATIONS[scope.currentScaleName].scale;
-          scope.timeline.scale = scope.currentScale;
-
           scope.currentScaleIndex = scope.timeline.ZOOM_SCALES.indexOf(scope.currentScaleName);
           scope.slider.slider('value', scope.currentScaleIndex + 1);
 

app/assets/javascripts/angular/timelines/models/mixins/ui.js

@@ -197,7 +197,12 @@ angular.module('openproject.timelines.models')
         index = this.zoomIndex;
       }
       index = Math.max(Math.min(this.ZOOM_SCALES.length - 1, index), 0);
+      var zoomScale = this.ZOOM_SCALES[index];
+      var scale = this.ZOOM_CONFIGURATIONS[zoomScale].scale;
+
       this.zoomIndex = index;
+      this.scale = scale;
+
       this.resetWidth();
       this.triggerResize();
       this.rebuildAll();