Typically, tiling window managers like XMonad do not have a system tray. If you want a system tray, you can use a standalone implementation like stalonetray or a status bar implementation with built-in system tray support, such as polybar.

Character width depends on the font, and Unicode Consortium does not provide explicit width definitions for all characters. There are characters that have ambiguous widths other than those defined as "Ambiguous (A)" in EastAsianWidth.txt. For example, "☀ (U+2600)" is defined as "Neutral (N)" in EastAsianWidth.txt, but its width may be full-width in a CJK font or an emoji font. This means that a non-East Asian character may be also the ambiguous-width character. Character width tables in default locales is problematic for both CJK and non-CJK users. You can create a custom locale to define a better character width table. wcwidth() respects defined by the locale. All TUI applications should consistently use wcwidth() to calculate the width of the character without an embedded character width table. If there is a mismatch in character width between applications, the screen will be broken.

XMonadで3列以上のレイアウトを提供するモジュールとして、xmonad-contribのThreeColumnsとMultiColumnsが存在する。ThreeColumnsは3列固定のレイアウトで、MultiColumnsは列数が動的に増減するレイアウトだ。しかし、いずれのレイアウトも筆者の要求を満たすものではなく、新しいレイアウトを独自に作成するに至った。