Steps to reproduce

1. Create a test page with basic template and add an html component with some content
2. Modify the html component definition to add writable: false in }}{{/mtk/templates/components/html.yaml
3. Go to pages-app and open the page created in step 1 and select the html component
4. Add a new html component

Expected results

According to the purpose of the writable property: 

So in step 3, the component cannot be edited whereas in step 4 you shouldn't be able to add any value

Actual results

The edit icon from the component bar disappears accordingly but edit component action in the action bar remains available so actually editors can edit the component. When creating a new component in step 4, value can also be assigned.