Quite a few big new features, improvements, and bug fixes made their way into Firefox Developer Edition 39. Update your Firefox [Developer Edition][dev-ed], or [Nightly][nightly] builds to try them out!
The [Inspector][inspector] now allows you to move elements around via [drag and drop][dnd]. Click and hold on an element and then drag it to where you want it to go. This feature was added by contributor Mahdi Dibaiee.
[![Drag and Drop][dnd-poster]][dnd-video]
Back in [Firefox 33][fx33], a tooltip was added to the rule view to allow editing curves for cubic bezier CSS animations. In Developer Edition 39, we've greatly enhanced the tooltip's UX by adding various standard curves you can try right away, as well as cleaned up the overall appearance. This was added by new contributor John Giannakos.