### 25.5 TUI Configuration Variables

Several configuration variables control the appearance of TUI windows.

`set tui border-kind kind`

  Select the border appearance for the source, assembly and register windows. The possible values are the following:

  `space`

    Use a space character to draw the border.

  `ascii`

    Use ASCII characters ‘`+`’, ‘`-`’ and ‘`|`’ to draw the border.

  `acs`

    Use the Alternate Character Set to draw the border. The border is drawn using character line graphics if the terminal supports them.

`set tui border-mode mode`
`set tui active-border-mode mode`

  Select the display attributes for the borders of the inactive windows or the active window. The mode can be one of the following:

  `normal`

    Use normal attributes to display the border.

  `standout`

    Use standout mode.

  `reverse`

    Use reverse video mode.

  `half`

    Use half bright mode.

  `half-standout`

    Use half bright and standout mode.

  `bold`

    Use extra bright or bold mode.

  `bold-standout`

    Use extra bright or bold and standout mode.

`set tui tab-width nchars`

  Set the width of tab stops to be nchars characters. This setting affects the display of TAB characters in the source and assembly windows.

`set tui compact-source [on|off]`

  Set whether the TUI source window is displayed in “compact” form. The default display uses more space for line numbers and starts the source text at the next tab stop; the compact display uses only as much space as is needed for the line numbers in the current file, and only a single space to separate the line numbers from the source.

Note that the colors of the TUI borders can be controlled using the appropriate `set style` commands. See Output Styling.