diff --git a/dashboard/src/components/GraphItem.vue b/dashboard/src/components/GraphItem.vue
index 36a1f6521..c8245d3ab 100644
--- a/dashboard/src/components/GraphItem.vue
+++ b/dashboard/src/components/GraphItem.vue
@@ -53,6 +53,8 @@ function createGraphOptions({ yscale, period, highMark }) {
       tooltip: {
         enabled: false,
         external: function(context) {
+          if (!tooltipElem.value) return;
+
           const tooltipModel = context.tooltip;
           if (tooltipModel.opacity === 0) {
             tooltipElem.value.style.opacity = 0;