diff --git a/platform/features/timeline/res/templates/activity-gantt.html b/platform/features/timeline/res/templates/activity-gantt.html
index 1615431e91..8515872352 100644
--- a/platform/features/timeline/res/templates/activity-gantt.html
+++ b/platform/features/timeline/res/templates/activity-gantt.html
@@ -20,7 +20,7 @@
  at runtime from the About dialog for additional information.
 -->
 <div class="t-timeline-gantt l-timeline-gantt s-timeline-gantt"
-     ng-class="{ sm: gantt.width(timespan, parameters.scroll, parameters.toPixels) < 25 }"
+     ng-class="timespan ? { sm: gantt.width(timespan, parameters.scroll, parameters.toPixels) < 25 } : {}"
      title="{{model.name}}"
      ng-controller="TimelineGanttController as gantt"
      ng-style="timespan ? {