I got more chance with code bellow. But Morph anchored in the text does not show up (only an empty frame), is it the expected behavior?
text := 'Figure DrGeo ' asText, TextConstants CR, DrGeoCanvas viewLess axesOn view asText, TextConstants CR, 'Ici...' asText. editor := RubEditingArea new updateTextWith: text; width: 400; openInWindow -- Dr. Geo http://drgeo.eu