fix dropdowns in Firefox

app/javascript/template_builder/area.vue

@@ -479,7 +479,7 @@ export default {
   methods: {
     buildDefaultName: Field.methods.buildDefaultName,
     closeDropdown () {
-      document.activeElement.blur()
+      this.$el.getRootNode().activeElement.blur()
     },
     maybeToggleDefaultValue () {
       if (['text', 'number'].includes(this.field.type)) {

app/javascript/template_builder/field.vue

@@ -392,7 +392,7 @@ export default {
       return this.sortedAreas[0] && this.$emit('scroll-to', this.sortedAreas[0])
     },
     closeDropdown () {
-      document.activeElement.blur()
+      this.$el.getRootNode().activeElement.blur()
     },
     addOption () {
       this.field.options.push({ value: '', uuid: v4() })

app/javascript/template_builder/field_submitter.vue

@@ -362,7 +362,7 @@ export default {
       this.$emit('new-submitter', newSubmitter)
     },
     closeDropdown () {
-      document.activeElement.blur()
+      this.$el.getRootNode().activeElement.blur()
     }
   }
 }

app/javascript/template_builder/field_type.vue

@@ -170,7 +170,7 @@ export default {
   },
   methods: {
     closeDropdown () {
-      document.activeElement.blur()
+      this.$el.getRootNode().activeElement.blur()
     }
   }
 }