Diff and merge
See every change between two documents, copy changes across, and build a merged version.
Diff shows two documents side by side with every changed line highlighted, and lets you move changes from one side to the other.
Start
- Open both documents.
- Click Diff in the footer's mode switcher, or right-click a tab → Diff with active.
- Pick the Left and Right tab.
Unchanged stretches are folded — click ⋯ 120 unchanged lines (show) to open them, or Show more to load the rest of a long diff.
Move changes
Each change (hunk) has buttons:
| Button | Effect |
|---|---|
| Apply to left | Copies the right side's version into the left document |
| Apply to right | Copies the left side's version into the right document |
| Add to merge | Adds this version of the change to the merge result |
Build a merged version
Use Add to merge on the changes you want, or Add all to merge. The Merge pane collects the result, ready to copy into a document.
Diff an AI result
You do not need two tabs to check an AI change: the AI result view has its own Diff tab. See Results, apply and undo.
Limits
Regular tabs are diffed in memory; very long documents show These documents are too large for in-memory diff — open them as large-file tabs instead. Diffing two large files is a Pro feature that runs on disk; see Compare and diff large files.