This files describes API changes in the editor_atto code.

=== 4.0 ===

* Two new helper functions have been added to lib/editor/atto
to handle enable/disable the empty placeholder for empty content in the HTML source view:
  - enablePlaceholderForEmptyContent() - Handle to enable the empty placeholder for empty content
  - disablePlaceholderForEmptyContent() - Handle to disable the empty placeholder for empty content.

* One property have been added to lib/editor/atto to handle the state of the empty placeholder content.
  - enableAppropriateEmptyContent - Enable/disable the empty placeholder content.

=== 3.4 ===

* The following functions, previously used (exclusively) by upgrade steps are not available
  anymore because of the upgrade cleanup performed for this version. See MDL-57432 for more info:
    - atto_equation_update_librarygroup4_setting()

=== 3.0 ===

* Rangy updated to 1.3.0.
  Rangy has deprecated the createCssClassApplier function in this version (it is now createClassApplier).

=== 2.9 ===

* When adding a shortcut to the button of a plugin, atto will add a layer of validation
to ensure that only the required keys are pressed. However, if you are using a custom
keyConfig object you must validate the shortcut yourself. This is particularly important
for non-English keyboard users. For more information read the documentation of
EditorPluginButtons::_addKeyboardListener() and MDL-47133.
