Previous versions of your plugin were using the unicode of an icon instead of the class name. While using class names is trivial in a default setup of TinyMCE, it's nearly impossible to use it together with TinyMCE's valid_classes setting.
valid_classes does not accept wildcards like fa-* so you need to either add every possible icon class to valid_classes, or not use valid_classes at all.
With the unicode approach, only 2 classes would need to be added to valid_classes: fa and fa-spin
Perhaps it would be possible to make this a config option?
Previous versions of your plugin were using the unicode of an icon instead of the class name. While using class names is trivial in a default setup of TinyMCE, it's nearly impossible to use it together with TinyMCE's valid_classes setting.
valid_classes does not accept wildcards like fa-* so you need to either add every possible icon class to valid_classes, or not use valid_classes at all.
With the unicode approach, only 2 classes would need to be added to valid_classes: fa and fa-spin
Perhaps it would be possible to make this a config option?