We created a list of placeholder selectors in placeholderSelectors option.
The purpose of this list is to indicate the contents that are only shown
in the editor and not to the users, by that way, we can decide to apply or
not to apply rules, styles, etc... to these contents
Part of MDL-75966
This commit adds TinyMCE version 6.1 into Moodle core.
A basic editor implementation is included, along with Moodle loader, and
basic Plugin API for Moodle. The Plugin API will be extended and
improved in future changes.
A new subplugin is defined for this plugin.
Huong Nguyen