diff --git a/src/lib/constants.js b/src/lib/constants.js
index b9afc41cb1..a7aaef5ad7 100644
--- a/src/lib/constants.js
+++ b/src/lib/constants.js
@@ -129,6 +129,7 @@ export const ANNOTATOR_EVENT = {
     fetch: 'annotationsfetched',
     error: 'annotationerror',
     scale: 'scaleannotations',
+    visibilityToggle: 'annotationvisibilitytoggle',
 };
 
 export const BROWSERS = {
diff --git a/src/lib/viewers/BaseViewer.js b/src/lib/viewers/BaseViewer.js
index d267c0f0c5..cdb8b5690b 100644
--- a/src/lib/viewers/BaseViewer.js
+++ b/src/lib/viewers/BaseViewer.js
@@ -545,6 +545,7 @@ class BaseViewer extends EventEmitter {
      */
     handleFullscreenEnter() {
         this.resize();
+        this.emit(ANNOTATOR_EVENT.visibilityToggle);
     }
 
     /**
@@ -554,6 +555,7 @@ class BaseViewer extends EventEmitter {
      */
     handleFullscreenExit() {
         this.resize();
+        this.emit(ANNOTATOR_EVENT.visibilityToggle);
     }
 
     /**