horizontal scrollable doesn’t displayed

Hello
I need to display a “wide table” meaning a table with many columns
I have selected the option – Scrollable Check this checkbox if you would like this table to be horizontal scrollable.
But no horizontal scrollable appears
(I use a test web site with a minimum plugin installation)
An example of a web page with the table is:
http://doctoroffice365.com/test-post-001/
any idea \ advice?
best regards
Eyal