@Keerthi0555 I updated StyledTextEditor.js like below "rtePlugins": {"styles": {"features": "*","styles": {"eyebrow": {"text": "Eyebrow","cssName": "eyebrow"},.. and tried both "#styles" or "styles#eyebrow"in uiSettings like below"uiSettings": {"cui": {"additionalClasses": {"fullscreenstart": {"cla...