| category | menu-title | meta-title | meta-description | order | modified_at |
|---|---|---|---|---|---|
ckeditor4-migration |
Troubleshooting |
Migration from CKEditor 4 - Troubleshooting | CKEditor 5 Documentation |
Overcoming possible obstacles during your migration to CKEditor 5. |
50 |
2023-03-21 |
This article describes some issues that you may encounter when migrating from CKEditor 4 to CKEditor 5.
Why does the editor filter out my content (styles, classes, elements)? Where is config.allowedContent = true?
Unlike CKEditor 4, CKEditor 5 implements a custom {@link framework/architecture/editing-engine data model}. This means that every piece of content that is loaded into the editor needs to be converted to that model and then rendered back to the view.
Each kind of content must be handled by a dedicated plugin. For instance, the ckeditor5-basic-styles package handles HTML elements such as <b>, <i>, <u>, etc. along with their representation in the model. The feature defines the two–way conversion between the HTML (view) and the editor model.
If you load some content that is not recognizable to any of the editor features, it will be dropped. If you want all the HTML5 elements to be supported, you need to write plugins to support them. Once you do that and load these plugins into your editor instance, CKEditor 5 will no longer filter anything out.
You may also use the {@link features/general-html-support General HTML support} functionality to enable HTML features that are not explicitly supported by CKEditor 5 plugins.
There is no such thing as the contents.css file anymore. This is because in CKEditor 5 the features bring their own content styles, {@link getting-started/setup/css provided via CSS files}.
Refer to {@link framework/how-tos#how-to-insert-some-content-into-the-editor this CKEditor 5 How-to question}.
Refer to {@link framework/how-tos#how-to-list-all-instances-of-the-editor this CKEditor 5 How-to question}.