After spending over an hour making changes to a page, I tried to alter the style of tabs (in the tabs block) but wasnt sure how to do so - so tried editing the font style.  After doing that I lost the content for each tab (have no idea what I did but the content was gone and I didnt notice that until after I clicked the save button to see how it functioned live).

Going back to the editor is when I noticed the content under each tab had gone.  
Lucky for me I had the page open in another browser tab so I was able to copy and save the content text but Im wondering if its not possible to just revert back to a previous restore point or similar in such a case?