Available in version 3.6 or later.
You can add buttons to a toolbar using Shortcuts advanced setting. You can also add toolbar buttons for custom external viewers using ExternalViewers.

Show, hide or overlay the toolbar #

Ver 3.7+: the Toolbar advanced setting controls how the toolbar is shown:
  • show : toolbar is pinned at the top of the window (the default)
  • hide : no toolbar
  • overlay : the toolbar floats over the page, sized to its natural width and horizontally centered. It’s hidden by default and only revealed when the mouse moves near the top of the page
Press F8 (the Toggle Toolbar command) to cycle through the modes: show → overlay → hide.
Toolbar = overlay
To customize toolbar:
  • use Settings / Advanced Options... menu (or Ctrl + K Command Palette, type adv to narrow down and select Advanced Options... command)
  • this opens default .txt editor with advanced settings file
  • find Shortcuts array and add new shortcut definitions
Example using text labels (ToolbarText):
Shortcuts [
    [
        Cmd = CmdPrevTab
        ToolbarText = Prev Tab
    ]
    [
        Cmd = CmdNextTab
        ToolbarText = Next Tab
    ]
    [
        Name = Send By Mail
        Cmd = CmdSendByEmail
        Key = Shift + M
        ToolbarText = ✉
    ]
    [
        Cmd = CmdNavigateBack
        ToolbarText = ←
    ]
    [
        Cmd = CmdNavigateForward
        ToolbarText = →
    ]
]
Explanation:
  • CmdNextTab is one of the commands
  • Next Tab will be shown in the toolbar
If you provide Name, it’ll be available in Command Palette.
See customize shortcuts for more complete docs on Shortcuts advanced setting.
See customize external viewers for adding external-viewer toolbar buttons.

Using SVG icons #

Ver 3.7+: set ToolbarSvgIcon to an SVG icon. The icon is rendered like built-in toolbar icons (theme text/background colors are applied automatically).
If both ToolbarSvgIcon and ToolbarText are set, the icon is used.
Use Tabler Icons SVGs (24×24, stroke="currentColor", fill="none") for best results — the built-in toolbar icons use the same format.
Example:
Shortcuts [
    [
        Cmd = CmdNavigateBack
        Name = Back
        ToolbarSvgIcon = <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><rect x="0" y="0" width="24" height="24" stroke="none"></rect><path d="M9 14l-4 -4l4 -4" /><path d="M5 10h11a4 4 0 1 1 0 8h-1" /></svg>
    ]
    [
        Cmd = CmdNavigateForward
        Name = Forward
        ToolbarSvgIcon = <svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="1" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><rect x="0" y="0" width="24" height="24" stroke="none"></rect><path d="M15 14l4 -4l-4 -4" /><path d="M19 10h-11a4 4 0 1 0 0 8h1" /></svg>
    ]
]
Name is used as the toolbar button tooltip. If omitted, the command’s default name is used.

Using Unicode symbols #

As an alternative to SVG, you can use Unicode symbols in ToolbarText — they are drawn as button labels using the UI font.
Symbols supported by Windows’ Segoe UI font: http://zuga.net/articles/unicode-all-characters-supported-by-the-font-segoe-ui/
To find a symbol you can search for example for arrow and then copy & paste the symbol (e.g. ) into settings file.