I am unable to see the different tabs of a tabset

Hi. I created a tabset. Everything was fine, i had put some chanrts on 4 different tabs, and then when i shut it down and opened it up again, i have been unable to click on anything or see anything other than the first tab. when i hit preview, i can see all of the other tabs and click on the and see my charts, but i am unable to edit.

any suggestions?