This is a CKEditor thing, not a Composr thing. They might have fixed it in v5, but we're using v4, which is a very old version. Unfortunately, because CKEditor changed their license in v5 to one not compatible with Composr, we cannot upgrade CKEditor to v5.

Therefore, CKEditor will probably be entering "non-maintained" status. If someone would like to help maintain it or implement a different editor in Composr, please feel free to create an issue and sponsor it.