Full Documentation — installation, showing the tab bar, adding tabs, moving tabs between areas, splitting with a tab, area edges, locked tabs, saving & loading, and settings.

Quick start

1. Install: drag the downloaded zip into the Blender window (or Edit > Preferences > Add-ons > Install from Disk…).
2. Start in either place: press Ctrl+T in any editor and search for the one you want, or click the Tabs button in the editor's header to raise an empty bar. Both get you a tab bar — the shortcut skips straight to adding a tab.
3. From there: + at the end of the bar adds another, and right-click a tab for its menu or the bar for the whole-bar one. Each tab is a full editor and keeps its own state.
4. Drag a tab to move it: onto another bar and it lands there, onto a bar-less header and that editor gains a bar, anywhere else and it tears off into its own window. Hold Shift on the drop to split the editor under the cursor instead — add Spacebar and the seam follows your cursor.

Tabs are saved into the .blend and come back with the file.