Act on several tabs at once

You can select several rows in the panel and act on all of them at once.

You read through a dozen Fastmail search results in tabs, and four of them are done.

Steps

In the panel, ⌘-click (Ctrl-click on Windows and Linux) each row you want. To take in every row between two, click the first, then Shift-click the last.
Right-click one of the selected rows.
Choose what to do with them: Close, Move to group, New group with selection, or Move to Workspace.

⌘-clicking a selected row takes it out of the selection.
Selecting a row this way doesn’t show its page. The page on screen stays as it was.
You can drag the selected rows together. They land in their order where you drop them. A dragged selection never makes a group or a Split.
Close works only when every selected row is a tab. To remove a group, use Delete group… on it.
Closing several tabs offers Undo at the bottom of the panel for 8 seconds.
The other entries in the menu, such as Rename, are dimmed while several rows are selected.
From the keyboard, Shift+↑ and Shift+↓ add rows to the selection, and Ctrl+Space adds or removes the focused row. Escape clears the selection.
Clicking a row without ⌘ or Shift clears the selection.