Zed just had one of its busiest weeks. The team shipped v1.15 of the editor with a handful of quality-of-life improvements, and simultaneously announced Delta, a brand-new standalone application that rethinks what a coding environment looks like when AI agents are doing most of the writing.

The v1.15 headliner: diffing against your default branch

The most immediately useful addition in v1.15 is a new git.diff_base setting. Before this, Zed's editor gutters, file-status colors, and git: diff command only showed changes relative to your last commit (HEAD). Now you can choose to show all current-branch changes against the default branch's merge base instead. That distinction matters a lot in practice.

If you're three days into a feature branch with 40 commits, the old behavior only told you what you hadn't committed yet. The new "default_branch" mode tells you everything your branch has changed relative to main -- the full picture of your work, right in the gutter. The setting is also available as "Diff Against Default Branch" in the editor controls menu , so you don't need to touch a config file to try it.

Credit goes to community contributor samuelcolvin for an earlier implementation that the Zed team built on top of.

Web dev improvements worth knowing

Web developers also get linked editing for custom elements in JSX and TSX, and Emmet completions in return and arrow-function bodies. The linked editing piece is the more impactful one: if you rename a custom element tag like <custom-el>, its matching closing tag updates automatically. Previously this only worked for standard HTML elements.

A few other smaller additions round out the release:

• Support for dragging files from the Project Panel to external apps on macOS and Linux Wayland.