diff --git a/ui/owner-ui-state.js b/ui/owner-ui-state.js
index 9d82771..3d47ef9 100644
--- a/ui/owner-ui-state.js
+++ b/ui/owner-ui-state.js
@@ -14,6 +14,14 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * @enum
+ */
+const OwnerUIStateEventType = {
+  EXPAND_SUGGESTION: 'expandSuggestion',
+};
+
 /**
  * For states used in code owners plugin across multiple components.
  */
@@ -21,7 +29,7 @@
   constructor() {
     this._expandSuggestion = false;
     this._listeners = new Map();
-    this._listeners.set('expandSuggestion', []);
+    this._listeners.set(OwnerUIStateEventType.EXPAND_SUGGESTION, []);
   }
 
   get expandSuggestion() {
@@ -30,7 +38,7 @@
 
   set expandSuggestion(value) {
     this._expandSuggestion = value;
-    this._listeners.get('expandSuggestion').forEach(cb => {
+    this._listeners.get(OwnerUIStateEventType.EXPAND_SUGGESTION).forEach(cb => {
       try {
         cb(value);
       } catch (e) {
@@ -39,9 +47,23 @@
     });
   }
 
+  _subscribeEvent(eventType, cb) {
+    this._listeners.get(eventType).push(cb);
+    return () => {
+      this._unsubscribeEvent(eventType, cb);
+    };
+  }
+
+  _unsubscribeEvent(eventType, cb) {
+    this._listeners.set(
+        eventType,
+        this._listeners.get(eventType).filter(handler => handler !== cb)
+    );
+  }
+
   onExpandSuggestionChange(cb) {
-    this._listeners.get('expandSuggestion').push(cb);
+    return this._subscribeEvent(OwnerUIStateEventType.EXPAND_SUGGESTION, cb);
   }
 }
 
-export const ownerState = new OwnerUIState();
\ No newline at end of file
+export const ownerState = new OwnerUIState();
diff --git a/ui/suggest-owners-trigger.js b/ui/suggest-owners-trigger.js
index 09fd6f8..2c0ccc0 100644
--- a/ui/suggest-owners-trigger.js
+++ b/ui/suggest-owners-trigger.js
@@ -22,6 +22,11 @@
     return 'suggest-owners-trigger';
   }
 
+  constructor(props) {
+    super(props);
+    this.expandSuggestionStateUnsubscriber = undefined;
+  }
+
   static get properties() {
     return {
       change: Object,
@@ -78,9 +83,18 @@
 
   connectedCallback() {
     super.connectedCallback();
-    ownerState.onExpandSuggestionChange(expanded => {
-      this.expanded = expanded;
-    });
+    this.expandSuggestionStateUnsubscriber = ownerState
+        .onExpandSuggestionChange(expanded => {
+          this.expanded = expanded;
+        });
+  }
+
+  disconnnectedCallback() {
+    super.disconnectedCallback();
+    if (this.expandSuggestionStateUnsubscriber) {
+      this.expandSuggestionStateUnsubscriber();
+      this.expandSuggestionStateUnsubscriber = undefined;
+    }
   }
 
   onInputChanged(restApi, change) {
diff --git a/ui/suggest-owners.js b/ui/suggest-owners.js
index 9919e54..2e1a487 100644
--- a/ui/suggest-owners.js
+++ b/ui/suggest-owners.js
@@ -24,6 +24,11 @@
     return 'owner-group-file-list';
   }
 
+  constructor() {
+    super();
+    this.expandSuggestionStateUnsubscriber = undefined;
+  }
+
   static get properties() {
     return {
       files: Array,
@@ -327,30 +332,40 @@
 
   connectedCallback() {
     super.connectedCallback();
-    ownerState.onExpandSuggestionChange(expanded => {
-      this.hidden = !expanded;
-      if (expanded) {
-        // this is more of a hack to let reivew input lose focus
-        // to avoid suggestion dropdown
-        // gr-autocomplete has a internal state for tracking focus
-        // that will be canceled if any click happens outside of
-        // it's target
-        // Can not use `this.async` as it's only available in
-        // legacy element mixin which not used in this plugin.
-        Polymer.Async.timeOut.run(() => this.click(), 100);
+    this.expandSuggestionStateUnsubscriber = ownerState
+        .onExpandSuggestionChange(expanded => {
+          this.hidden = !expanded;
+          if (expanded) {
+            // this is more of a hack to let reivew input lose focus
+            // to avoid suggestion dropdown
+            // gr-autocomplete has a internal state for tracking focus
+            // that will be canceled if any click happens outside of
+            // it's target
+            // Can not use `this.async` as it's only available in
+            // legacy element mixin which not used in this plugin.
+            Polymer.Async.timeOut.run(() => this.click(), 100);
 
-        // start fetching suggestions
-        if (!this._suggestionsTimer) {
-          this._suggestionsTimer = setInterval(() => {
-            this._pollingSuggestions();
-          }, SUGGESTION_POLLING_INTERVAL);
+            // start fetching suggestions
+            if (!this._suggestionsTimer) {
+              this._suggestionsTimer = setInterval(() => {
+                this._pollingSuggestions();
+              }, SUGGESTION_POLLING_INTERVAL);
 
-          // poll immediately to kick start the fetching
-          this.reporting.reportLifeCycle('owners-suggestions-fetching-start');
-          this._pollingSuggestions();
-        }
-      }
-    });
+              // poll immediately to kick start the fetching
+              this.reporting
+                  .reportLifeCycle('owners-suggestions-fetching-start');
+              this._pollingSuggestions();
+            }
+          }
+        });
+  }
+
+  disconnectedCallback() {
+    super.disconnectedCallback();
+    if (this.expandSuggestionStateUnsubscriber) {
+      this.expandSuggestionStateUnsubscriber();
+      this.expandSuggestionStateUnsubscriber = undefined;
+    }
   }
 
   onInputChanged(restApi, change) {