diff --git a/ext/bg/js/yomichan.js b/ext/bg/js/yomichan.js
index e7e674ac..062e5e72 100644
--- a/ext/bg/js/yomichan.js
+++ b/ext/bg/js/yomichan.js
@@ -50,9 +50,9 @@ class Yomichan {
 
     onMessage(request, sender, callback) {
         const {action, params} = request, handlers = {
-            canAddNotes: ({definitions}) => this.ankiInvoke('canAddNotes', definitions, callback),
-            findKanji:   ({text}) => callback(this.translator.findKanji(text)),
-            findTerm:    ({text}) => callback(this.translator.findTerm(text)),
+            canAddNotes: (definitions) => this.ankiInvoke('canAddNotes', definitions, callback),
+            findKanji:   (text) => callback(this.translator.findKanji(text)),
+            findTerm:    (text) => callback(this.translator.findTerm(text)),
             getOptions:  () => callback(this.options),
             getState:    () => callback(this.state),
             renderText:  ({data, template}) => callback(Handlebars.templates[template](data))
diff --git a/ext/fg/js/api.js b/ext/fg/js/api.js
index da5f6d5a..9026c8d3 100644
--- a/ext/fg/js/api.js
+++ b/ext/fg/js/api.js
@@ -21,30 +21,30 @@
 // Background APIs
 //
 
-function sendMessage(action, params, callback) {
+function bgSendMessage(action, params, callback) {
     chrome.runtime.sendMessage({action: action, params: params}, callback);
 }
 
-function findTerm(text, callback) {
-    sendMessage('findTerm', {text: text}, callback);
+function bgFindTerm(text, callback) {
+    bgSendMessage('findTerm', text, callback);
 }
 
-function findKanji(text, callback) {
-    sendMessage('findKanji', {text: text}, callback);
+function bgFindKanji(text, callback) {
+    bgSendMessage('findKanji', text, callback);
 }
 
-function renderText(data, template, callback) {
-    sendMessage('renderText', {data: data, template: template}, callback);
+function bgRenderText(data, template, callback) {
+    bgSendMessage('renderText', {data: data, template: template}, callback);
 }
 
-function getOptions(callback) {
-    sendMessage('getOptions', null, callback);
+function bgGetOptions(callback) {
+    bgSendMessage('getOptions', null, callback);
 }
 
-function getState(callback) {
-    sendMessage('getState', null, callback);
+function bgGetState(callback) {
+    bgSendMessage('getState', null, callback);
 }
 
-function canAddNotes(definitions, callback) {
-    sendMessage('canAddNotes', {definitions: definitions}, callback);
+function bgCanAddNotes(definitions, callback) {
+    bgSendMessage('canAddNotes', definitions, callback);
 }
diff --git a/ext/fg/js/client.js b/ext/fg/js/client.js
index 11190869..e7300874 100644
--- a/ext/fg/js/client.js
+++ b/ext/fg/js/client.js
@@ -37,9 +37,9 @@ class Client {
         window.addEventListener('scroll', (e) => this.hidePopup());
         window.addEventListener('resize', (e) => this.hidePopup());
 
-        getOptions((opts) => {
+        bgGetOptions((opts) => {
             this.setOptions(opts);
-            getState((state) => this.setEnabled(state === 'enabled'));
+            bgGetState((state) => this.setEnabled(state === 'enabled'));
         });
     }
 
@@ -101,19 +101,21 @@ class Client {
         }
 
         range.setLength(this.options.scanLength);
-        findTerm(range.text(), ({definitions, length}) => {
+        bgFindTerm(range.text(), ({definitions, length}) => {
             if (length === 0) {
                 this.hidePopup();
             } else {
                 range.setLength(length);
-                renderText(
+                bgRenderText(
                     {defs: definitions, root: this.fgRoot, options: this.options},
                     'term-list.html',
                     (content) => {
                         this.definitions = definitions;
                         this.showPopup(range, content);
-                        canAddNotes(definitions, (states) => {
-                            states.forEach((state, index) => this.popup.sendMessage('setActionState', {index: index, state: state}));
+                        bgCanAddNotes(definitions, (states) => {
+                            if (states !== null) {
+                                states.forEach((state, index) => this.popup.sendMessage('setActionState', {index: index, state: state}));
+                            }
                         });
                     }
                 );
@@ -129,8 +131,8 @@ class Client {
     }
 
     actionDisplayKanji(kanji) {
-        findKanji(kanji, (definitions) => {
-            renderText(
+        bgFindKanji(kanji, (definitions) => {
+            bgRenderText(
                 {defs: definitions, root: this.fgRoot, options: this.options},
                 'kanji-list.html',
                 (content) => {