action

The action API was introduced as part of the manifest v3 specification and first appeared in Thunderbird 105. It is identical to the old browserAction API and very similar to Firefox’s action API.

Use the action API to add a button to Thunderbird’s unified toolbar. In addition to its icon, an action button can also have a tooltip, a badge, and a popup.

Manifest file properties

[action]

(object, optional)

[allowed_spaces]

(array of string, optional)

Defines for which spaces the action button will be added to Thunderbird’s unified toolbar. Defaults to only allowing the action in the mail space. The default space is for tabs that don’t belong to any space. If this is an empty array, the action button is shown in all spaces.

Supported values:

mail

addressbook

calendar

tasks

chat

settings

default

[browser_style]

(boolean, optional)

Enable browser styles. See the MDN documentation on browser styles for more information.

[default_icon]

(IconPath, optional)

The paths to one or more icons for the action button.

[default_label]

(string, optional)

The label of the action button, defaults to its title. Can be set to an empty string to not display any label. If the containing toolbar is configured to display text only, the title will be used as fallback.

[default_popup]

(string, optional)

The html document to be opened as a popup when the user clicks on the action button. Ignored for action buttons with type menu.

[default_title]

(string, optional)

The title of the action button. This shows up in the tooltip and the label. Defaults to the add-on name.

[default_windows]

(array of string, optional)

Defines the windows, the action button should appear in. Defaults to showing it only in the normal Thunderbird window, but can also be shown in the messageDisplay window.

Supported values:

normal

messageDisplay

[theme_icons]

(array of ThemeIcons, optional)

Specifies dark and light icons to be used with themes. The light icon is used on dark backgrounds and vice versa. Note: The default theme uses the default_icon for light backgrounds (if specified).

[type]

(string, optional)

Specifies the type of the button. Default type is button.

Supported values:

button

menu

Note

A manifest entry named action is required to use messenger.action.*.

Functions

setTitle(details)

Sets the title of the action button. Is used as tooltip and as the label.

Parameters

details

(object)

title

(string or null)

A string the action button should display as its label and when moused over. Cleared by setting it to null or an empty string (title defined the manifest will be used).

[tabId]

(integer, optional)

Sets the title only for the given tab.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

getTitle(details)

Gets the title of the action button.

Parameters

details

(object)

[tabId]

(integer, optional)

Specifies for which tab the title should be retrieved. If no tab is specified, the global value is retrieved.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

Return type (Promise)

string

setLabel(details)

– [Added in TB 84.0b3, backported to TB 78.6.1]

Sets the label of the action button. Can be used to set different values for the tooltip (defined by the title) and the label. Additionally, the label can be set to an empty string, not showing any label at all.

Parameters

details

(object)

label

(string or null)

A string the action button should use as its label, overriding the defined title. Can be set to an empty string to not display any label at all. If the containing toolbar is configured to display text only, its title will be used. Cleared by setting it to null.

[tabId]

(integer, optional)

Sets the label only for the given tab.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

getLabel(details)

– [Added in TB 84.0b3, backported to TB 78.6.1]

Gets the label of the action button.

Parameters

details

(object)

[tabId]

(integer, optional)

Specifies for which tab the label should be retrieved. If no tab is specified, the global label is retrieved.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

Return type (Promise)

string

setIcon(details)

Sets the icon for the action button. Either the path or the imageData property must be specified.

Parameters

details

(object)

[imageData]

The image data for one or more icons for the action button.

[path]

(IconPath, optional)

The paths to one or more icons for the action button.

[tabId]

(integer, optional)

Sets the icon only for the given tab.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

setPopup(details)

Sets the html document to be opened as a popup when the user clicks on the action button.

Parameters

details

(object)

popup

(string or null)

The html file to show in a popup. Can be set to an empty string to not open a popup. Cleared by setting it to null (popup value defined the manifest will be used).

[tabId]

(integer, optional)

Sets the popup only for the given tab.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

getPopup(details)

Gets the html document set as the popup for this action button.

Parameters

details

(object)

[tabId]

(integer, optional)

Specifies for which tab the popup document should be retrieved. If no tab is specified, the global value is retrieved.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

Return type (Promise)

string

setBadgeText(details)

Sets the badge text for the action button. The badge is displayed on top of the icon.

Parameters

details

(object)

text

(string or null)

Any number of characters can be passed, but only about four can fit in the space. Cleared by setting it to null or an empty string.

[tabId]

(integer, optional)

Sets the badge text only for the given tab.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

getBadgeText(details)

Gets the badge text of the action button.

Parameters

details

(object)

[tabId]

(integer, optional)

Specifies for which tab the badge text should be retrieved. If no tab is specified, the global label is retrieved.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

Return type (Promise)

string

setBadgeBackgroundColor(details)

Sets the background color for the badge.

Parameters

details

(object)

color

(string or ColorArray or null)

The color to use as background in the badge. Cleared by setting it to null or an empty string.

[tabId]

(integer, optional)

Sets the background color for the badge only for the given tab.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

getBadgeBackgroundColor(details)

Gets the badge background color of the action button.

Parameters

details

(object)

[tabId]

(integer, optional)

Specifies for which tab the badge background color should be retrieved. If no tab is specified, the global label is retrieved.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

Return type (Promise)

enable([tabId])

Enables the action button for a specific tab (if a tabId is provided), or for all tabs which do not have a custom enable state. Once the enable state of a tab has been updated individually, all further changes to its state have to be done individually as well. By default, an action button is enabled.

Parameters

[tabId]

(integer, optional)

The id of the tab for which you want to modify the action button.

disable([tabId])

Disables the action button for a specific tab (if a tabId is provided), or for all tabs which do not have a custom enable state. Once the enable state of a tab has been updated individually, all further changes to its state have to be done individually as well.

Parameters

[tabId]

(integer, optional)

The id of the tab for which you want to modify the action button.

isEnabled(details)

Checks whether the action button is enabled.

Parameters

details

(object)

[tabId]

(integer, optional)

Specifies for which tab the state should be retrieved. If no tab is specified, the global value is retrieved.

[windowId]

(integer, optional) Unsupported.

Will throw an error if used.

Return type (Promise)

boolean

openPopup([options])

Opens the action’s popup window in the specified window. Defaults to the current window. Returns false if the popup could not be opened because the action has no popup, is of type menu, is disabled or has been removed from the toolbar.

Parameters

[options]

(object, optional)

An object with information about the popup to open.

[windowId]

(integer, optional)

Defaults to the current window.

Return type (Promise)

boolean

Events

onClicked

Fired when an action button is clicked. This event will not fire if the action has a popup. This is a user input event handler. For asynchronous listeners some restrictions apply.

Parameters for onClicked.addListener(listener)

listener(tab, info)

A function that will be called when this event occurs.

Parameters passed to the listener function

tab

(Tab)

– [Added in TB 74.0b2]

[info]

(OnClickData, optional)

– [Added in TB 74.0b2]

Types

ActionManifest

ColorArray

An array of four integers in the range [0,255] that make up the RGBA color. For example, opaque red is [255, 0, 0, 255].

array of integer

ImageDataDictionary

A dictionary object to specify multiple ImageData objects in different sizes, so the icon does not have to be scaled for a device with a different pixel density. Each entry is a name-value pair with value being an ImageData object, and name its size. Example:

{
  "16": icon16,
  "32": icon32
}

See the MDN documentation about choosing icon sizes for more information on this.

object

ImageDataType

Pixel data for an image. Must be an ImageData object (for example, from a canvas element).

OnClickData

– [Added in TB 74.0b2]

Information sent when an action button is clicked.

object

modifiers

(array of string)

An array of keyboard modifiers that were held while the menu item was clicked.

Supported values:

Shift

Alt

Command

Only available on macOS.

Ctrl

Not available on macOS.

MacCtrl

Only available on macOS, but of limited use in a click event: Holding down the CTRL key while clicking with the mouse is referred to as a ‘CTRL click’ under macOS and is interpreted as a right mouse click. In a default profile the dom.event.treat_ctrl_click_as_right_click.disabled preference is not enabled and the MacCtrl modifier key is not forwarded to the API.

[button]

(integer, optional)

An integer value of button by which menu item was clicked.

External Types

The following types are not defined by this API, but by the underlying Mozilla WebExtension code base. They are included here, because there is no other public documentation available.

IconPath

Either a string to specify a relative path of a single icon to be used for all sizes, or a dictionary object to specify paths for multiple icons in different sizes, so the icon does not have to be scaled for a device with a different pixel density. Each entry is a name-value pair with value being a relative path to an icon file, and name its size. Example:

{
  "16": "icon16.png",
  "32": "icon32.png"
}

See the MDN documentation about choosing icon sizes for more information on this.

ThemeIcons

Define a set of icons for themes depending on whether Thunderbird detects that the theme uses dark or light text. All provided URLs must be relative to the manifest.json file.

object

dark

(string)

A URL pointing to an icon. This icon displays when a theme using dark text is active (such as the Light theme, and the Default theme if no default_icon is specified).

light

(string)

A URL pointing to an icon. This icon displays when a theme using light text is active (such as the Dark theme).

size

(integer)

The size of the two icons in pixels, for example 16 or 32.