Last Tab

Description

When you close the last tab in a window, this extension will open a new tab and prevent the window from being closed. Because of Chrome API's restrictions, the extension works by creating a pinned tab without a title that stays open. When that tab is activated, the extension will activate the first real tab.

There is a "Open new tab on click" option that does what the name says. It will change the tab icon to indicate its new behavior.

This extension is based on the "Keep One Pinned Tab" extension. I felt a rewrite was needed because the original extension was buggy and written in a way that made fixing it difficult.

There is a known issue with the "Open new tab on click" option where moving with Ctrl + Tab through tabs will open a new tab if you circle around to the first tab. Unfortunately, I don't know of a way to avoid that with the Chrome API.
However, I suppose that people who use shortcuts for moving through tabs will also use them for opening new tabs, so they won't need the "Open new tab on click" option.