Field with html editor tinymce the tables do no show lines solid standard

Dear reader

In the html editor tinymce the tables do no show border lines or only dashed.
I am using the latest updated scriptcase 9.
To change the borderline on a table it is cumbersome and sometimes I can not get it to work to change the line to solid.
Is there a way to set the borders default to solid ?

Furthermore is it possible to activate updates or new plugins of tinymce myself ?
I would like to have a spellchecker for instance in the htmleditor.

With kind regards

Stephan