User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.76 Safari/537.36

This is defined by the Firefox UI and based on your locale and supporting both sides would be too complicated for now

mmc and I are working on exciting new features for Lightbeam, including a sidebar. We'd love to be able to place it on the right side of the screen (or choose the side to place it on). This makes it easier to browse the web while leaving the sidebar open, and our idea is to use this to enable cross-request visualization of tracking domains. Generally, based on cultural background and the way in which text is read, sidebars are best placed at the "end of the line". For Western users, that's the right side of the screen.

Garrett, I agree completely with your reasoning. While I did not explain the feature request when I opened this issue, I did so for exactly that reason.

I don't think the premises are changed, plus the sidebar element is only one for all sidebars – exactly as the `width` issue, changing the placement would affect them all, see bug 919117. Looking also at bug 983545, it seems to me that what is needed is a different type of component rather than Sidebar, a panel like devtools panel that are per tab: I'm wondering if it would be easier just create a new component similar to devtools panel than reusing Sidebar for that purpose.

(In reply to Garrett Robinson [:grobinson] from comment #2) > Generally, based on cultural background and the way in which text is read, > sidebars are best placed at the "end of the line". For Western users, that's > the right side of the screen. If that's the case then it might be better to have all the Firefox sidebars moved to the right side.

I think it depends on the purpose you're using the sidebar for. In our case, it's to augment the page contents. Because it's secondary to the page contents and the user reads left to right, it makes sense for the page to appear first and the sidebar to appear second. I'm not sure whether all sidebars are augmenting the page. Bookmarks and history for example seem to be the primary objective of the user at the time and so I think they're fine currently on the left. I certainly wouldn't complain if you wanted to move all sidebars to the right as it seems a better fit for what I'm doing.

> If that's the case then it might be better to have all the Firefox sidebars moved to the right side. I agree with Ben's Comment 6. Also, what about users who read right-to-left (if we accept my reasoning from comment 2)? > Looking also at bug 983545, it seems to me that what is needed is a different type of component rather than Sidebar, a panel like devtools panel that are per tab This is actually what we would like to have as well. I only just realized last night in trying to implement this that Sidebars have per-window, not per-tab semantics (which is what I assumed, and what would be more useful to me).

(In reply to Garrett Robinson [:grobinson] from comment #7) > > If that's the case then it might be better to have all the Firefox sidebars moved to the right side. > > I agree with Ben's Comment 6. Also, what about users who read right-to-left Firefox should already be flipping the side the sidebar appears on for RTL language users.

The Sidebar API is intentionally constrained to the same behaviour as Firefox's own sidebars. This is the right thing to do for users even though it limits what developers can do. It's totally possible to implemtn your own sidebar using lower level apis, but this high-level api needs to remain consistent with Firefox' UX. Wontfixing, and interested to see if any custom sidebar modules in are developed in the community.

Hi Jeff, we have our own sidebar implementation and I believe we'll keep using it rather than the high-level API because it solves numerous issues for us (doesn't refresh when closing & opening, can put it on the righthand side, can control the width). Is there somewhere we should consider sharing it as a module if we wanted to open source it?

(In reply to Ben McCann from comment #10) > Is there somewhere we should consider sharing > it as a module if we wanted to open source it? That sounds splendid! Step 1 would be to publish it on github. We are working on being able to use npm as a package manager, it makes a lot of sense seeing as we use CommonJS modules.