Mouse

Lattice reads the mouse in both the terminal and the GPUI window.

Scrolling doesn't steal focus

The wheel scrolls whichever pane the pointer is over, and leaves the focused pane alone. So you can keep typing in one split while spinning through a reference file in another — no click first, and no getting bounced out of what you were doing. Vim, Helix and Zed all behave this way.

Clicking is the gesture that does move focus. Click into a split and you're in it.

Dragging gives you a Visual selection

A drag doesn't produce some separate "mouse selection" that only a Ctrl-C understands. It leaves you in Visual mode, with the region live, exactly as if you had pressed v and moved. So everything works on it:

• d deletes it, y yanks it, c changes it
• > indents it, gu lowercases it, : operates on its range
• o jumps to the other end, iw / ap expand it

Drag from where you want the selection to start; the anchor stays put while you move. A plain click ends the selection, as it does anywhere else.

Clicking links

In buffers that carry links — the dashboard, help pages — clicking a link follows it. Clicking anywhere else just moves the cursor, so ordinary text stays ordinary text.

Dragging across a link selects it instead of following it, which is how you copy a link's text.

The file tree and oil buffers deliberately don't work this way: a click there moves the cursor, and <CR> opens the entry under it. Otherwise you could never click a row without opening it.

Turning it off

ui.mouse is on by default, and it has one real cost: while Lattice is reading the mouse, your terminal emulator isn't. Its own click-drag text selection and middle-click paste stop working inside Lattice. Many terminals let you hold Shift to get them back — try that first, it is usually all you need.

If your terminal has no such override, or you'd rather it kept the mouse:

:set ui.mouse=false

That applies immediately, so flipping it off to copy something and back on afterwards is perfectly reasonable. To make it stick, put this in your config:

[ui]
mouse = false

The GPUI window ignores the option — it owns its own input, so listening for the mouse costs you nothing there.

What doesn't respond yet

• Full-screen programs inside :terminal. A terminal buffer gets ordinary editor gestures — scroll its scrollback, click to position, drag to select. Passing the mouse through to the program running inside it (so htop or a nested editor sees your clicks) is a separate piece of work and isn't built.
• Clicking in the gutter, on a fold marker, or on a sticky-context header. These are inert for now. Scrolling over them works, because the pane underneath is still the pane.
• Links in the help popup. :help currently opens as a floating popup rather than a pane, and clicks don't reach it yet. Links in the dashboard, and in help opened into a pane, work.