diff --git a/src/background/infrastructures/content-message-listener.js b/src/background/infrastructures/content-message-listener.js
index 58716fb..4fcc6a6 100644
--- a/src/background/infrastructures/content-message-listener.js
+++ b/src/background/infrastructures/content-message-listener.js
@@ -19,7 +19,11 @@ export default class ContentMessageListener {
   run() {
     browser.runtime.onMessage.addListener((message, sender) => {
       try {
-        return this.onMessage(message, sender).catch((e) => {
+        let ret = this.onMessage(message, sender);
+        if (!(ret instanceof Promise)) {
+          return {};
+        }
+        return ret.catch((e) => {
           return browser.tabs.sendMessage(sender.tab.id, {
             type: messages.CONSOLE_SHOW_ERROR,
             text: e.message,
diff --git a/src/background/repositories/find.js b/src/background/repositories/find.js
index 9482e78..6656c58 100644
--- a/src/background/repositories/find.js
+++ b/src/background/repositories/find.js
@@ -12,7 +12,8 @@ export default class FindRepository {
   }
 
   setKeyword(keyword) {
-    return this.cache.set(FIND_KEYWORD_KEY, keyword);
+    this.cache.set(FIND_KEYWORD_KEY, keyword);
+    return Promise.resolve();
   }
 }
 
diff --git a/src/background/usecases/link.js b/src/background/usecases/link.js
index f9e474a..1339fdf 100644
--- a/src/background/usecases/link.js
+++ b/src/background/usecases/link.js
@@ -8,8 +8,7 @@ export default class LinkInteractor {
   }
 
   openToTab(url, tabId) {
-    this.tabPresenter.open(url, tabId);
-
+    return this.tabPresenter.open(url, tabId);
   }
 
   async openNewTab(url, openerId, background) {
diff --git a/src/background/usecases/operation.js b/src/background/usecases/operation.js
index 86f39ca..7bf93e4 100644
--- a/src/background/usecases/operation.js
+++ b/src/background/usecases/operation.js
@@ -126,7 +126,7 @@ export default class OperationInteractor {
 
   async showCommand() {
     let tab = await this.tabPresenter.getCurrent();
-    this.consolePresenter.showCommand(tab.id, '');
+    return this.consolePresenter.showCommand(tab.id, '');
   }
 
   async showOpenCommand(alter) {
@@ -173,12 +173,12 @@ export default class OperationInteractor {
 
   async findStart() {
     let tab = await this.tabPresenter.getCurrent();
-    this.consolePresenter.showFind(tab.id);
+    return this.consolePresenter.showFind(tab.id);
   }
 
   async hideConsole() {
     let tab = await this.tabPresenter.getCurrent();
-    this.consolePresenter.hide(tab.id);
+    return this.consolePresenter.hide(tab.id);
   }
 
   onTabSelected(tabId) {