global-tab-line-mode toggles the display of
a tab line on the top screen line of each window. The Tab Line
shows special buttons (“tabs”) for each buffer that was displayed in
a window, and allows switching to any of these buffers by clicking the
corresponding button. Clicking on the + icon adds a new buffer
to the window-local tab line of buffers, and clicking on the x
icon of a tab deletes it. The mouse wheel on the tab line scrolls
the tabs horizontally.
Selecting the previous window-local tab is the same as typing C-x
previous-buffer), selecting the next tab is the
same as C-x RIGHT (
next-buffer). Both commands
support a numeric prefix argument as a repeat count.
You can customize the variable
tab-line-tabs-function to define
the preferred contents of the tab line. By default, it displays all
buffers previously visited in the window, as described above. But you
can also set it to display a list of buffers with the same major mode
as the current buffer, or to display buffers grouped by their major
mode, where clicking on the mode name in the first tab displays a list
of all major modes where you can select another group of buffers.
Note that the Tab Line is different from the Tab Bar (see Tab Bars). Whereas tabs on the Tab Bar at the top of each frame are used to switch between window configurations containing several windows with buffers, tabs on the Tab Line at the top of each window are used to switch between buffers in the window.