we don't need a details pane, it should be collapsed so we maximize the content area.
when we open the Library view from Show all downloads, looks like the details pane is not properly initialized, so it has the wrong size (it's too tall and covers most of the view). So this becomes a bit more important.
Created attachment 696147 [details] [diff] [review] patch v1.0 Since I'd like to enable the new view by default in Nightly, I want to address this. This patch is a first possibility, when registering a custom view allow to pass an optional options object. The only supported option for now is showDetailsPane. While working on this I found a possible typo in the view selectedNodes getter. I was thinking we may also use these options to customize the Library toolbar (like passing a sort of currentSet) to hide Views and add the Clear all downloads button. But I'm not sure if you had a different idea in mind.
Comment on attachment 696147 [details] [diff] [review] patch v1.0 I like it.
Backed out for failing browser_library_downloads.js: https://hg.mozilla.org/integration/mozilla-inbound/rev/311689a4858f
relanded, not culprit for the failure https://hg.mozilla.org/integration/mozilla-inbound/rev/9119f282e0c0