Service Portal HTML fields or variables do not have the option to increase the size or re-size the Editor window for better viewing as in UI16.
1. In Service Portal, navigate to Home > Community > Ask a Question
I.e. the "SQANDA Create Question" Widget that has a HTML field /sp?id=sqanda_new_question
Observe there is no way to re-size the editor window for HTML fields and variables in Service Portal.
2. From UI16, display the same form:
The option to re-size the window will be displayed in the right bottom corner of the TinyMCE HTML Editor.
This problem is under review and targeted to be fixed in a future release. To receive notifications when more information becomes available, subscribe to this Known Error article by clicking the Subscribe button at the top right of this form.