New Features in Ver 4.1

・Features
　・Choice of Search Engines
　　Search Engines can be disabled individually.
　・Shortcut key for toggling
　　Now you can set a shortcut key for toggling.

・Others
　・For Developers
　　Refactor code.

New Features in Ver 4.0

・Features
　・User Agent
　　Changing the user agent is available. This feature requires a host permission. Open the options page and enable the host permission to enable this feature. This feature effects all pages of extensions which you have installed.
　・Text Selection
　　Text selection in the sidebar is enabled.
　・Support scrolling on DuckDuckGo
　　Scroll bar is enabled on DuckDuckGo in the sidebar.

・Others
　・For Developers
　　Refactor code.

New Features in Ver 3.2.1

・Features
　・Permission
　　Change the permission for running a shortcut. Thus, this extension requires no permissions again.

New Features in Ver 3.2.0

・Features
　・Search Engine Icon
　　An icon of a search engine including an additional search engine is displayed in the context menu.
　・Tutorial
　　A tutorial can be opened by right clicking the icon of this extension.

・Others
　・For Users
　　Remove unnecessary permission. Tab permission is no longer required.
　・For Developers
　　Fetch API replaces XmlHttpRequest.
　　Reduce number of times of reading json files.
　　Refactor code.

New Features in Ver 3.1.0

・Features
　・Shortcut
　　Users can search with a shortcut key. The default is "Ctrl+Alt+S". The shortcut key can be edited (refer to this link). This feature requires an additional permission.

・Others
　・For Developers
　　Replace deprecated APIs.

New Features in Ver 3.0

・Features
　・Additional search engines by a user
　　Users can add a search engine in a options page. Also you can choose the site as a default a search engine. YouTube, Amazon, MDN, ... so many sites can be used.

・Others
　・For Developers
　　Remove unused values in messages.json.
　　Unify a format of br tags.

New Features in Ver 2.1

・Features
　・Icon
　　The icon of this addon has been added to the tool bar. The sidebar is displayed / reloaded quickly by pressing it. You can remove this icon if you don't need it.
　・Options
　　You can decide behavior of the icon in the toolbar by choosing options. The default is 'Reload', this reloads the page in the sidebar. Another option is 'Go back to Home', this replaces the page of the sidebar with the home of search engines. If you have chosen 'ask' option, 'Reload' option is used instead of 'Go back to Home' option.
・Others
　・For Developers
　　Remove checking the current url of the sidebar from sidebar.js because it is redundant. I did not know this script is not called when other url is set to the sidebar.