Diff opened tabs

Here are the quickest ways to diff two open tabs in VS Code:

1. Command Palette (fastest)

1. Focus the first tab.
2. Press Cmd+Shift+P and run File: Compare Active File With...
3. Pick the second file from the list; open editors appear at the top.

2. Open Editors panel (works for unsaved/untitled tabs too)

1. In the Explorer sidebar, expand Open Editors. If it's hidden, enable it from the ... menu at the top of Explorer.
2. Right-click the first tab and choose Select for Compare.
3. Right-click the second tab and choose Compare with Selected.

3. Explorer multi-select (for saved files)
Cmd+click both files in the file tree, then right-click and choose Compare Selected.