Can't edit a table

[lameira.marina 0]

Hi, I was working on a table and would like to continue it, but the + button which exist to add a column or line have disappeared and I can only write on already exihisting cells. The layout is also different, so that I cannot see the whole table on the screen, but I need to go through the scrollbar. What can I do to be able to edit the table again, the way it was before? 

[jefito 5,272]

Windows? Mac? Android? iOS? Web?

A screen shot might help.