June 9th, 2015
With Opera 30, we finally have support for sidebar extensions in the stable build! In other types of extensions, say, ones with popups, the popup window gets closed quickly, it’s cumbersome to open and close it all the time in case you use it often.
There are certain types of extensions where you might want it open all the time (or at least, a lot of the time), and we’ve added support for it in the form of sidebar extensions. The sidebar is a place on the left side of the browser which has room for additional functionality for the user. The sidebar consists of the icons list on the left hand side of the sidebar and the clicking on an icon from the icons list will open its corresponding panel.
The panel is an HTML page specified inside the extension which will house the main content of the extension. Every sidebar action must have a panel page specified. You don’t need to define any special permission in the manifest to make a sidebar extension, though you do have to define details regarding it in the manifest (just like you do with browser actions). In fact, for sidebar extensions, we call them sidebar actions.
Also note that it is possible to have extensions which have a button on the toolbar, as well as a sidebar. So you can have your existing extension, which uses, say, a popup and add support for it in the sidebar as well.
We’ve had support for sidebar extensions in the Developer and Beta channels for a while now, and some people in the extension community have already made some great extensions with sidebar support. A few of them worth checking out are listed below.
Site Settings Sidebar
Site Settings Sidebar enables you to control site specific settings from the sidebar itself. It makes it really convenient to change such things like geolocation, zoom and camera settings, etc.
V7 Bookmarks and Notes
Vux777 has created some great extensions, some of which utlize the sidebar too. In particular, take a look at the V7 Bookmarks extension, which puts all your bookmarks on the sidebar, and does a lot more too. Another one of his is V7 Notes which re-creates a notes panel that some of our long-time users might be very familar with 😉
This is by yours truly. Browse++ Sidebar is a quick port of an extension I had created a while ago, called Browse++. I think it works better as a sidebar extension. You can get a vertical list of all your open tabs (and switch to them), save notes, and also re-open any of the last 50 closed tabs.
You can browse more sidebar extensions by going to our addons store.