List pages in SharePoint contain “List Tools” tab on top of the page, and a drop down to let us select different views of the list, these are helpful function and we quickly get used to them.
But they are taken out if another web part is added on the page, even if it’s hidden or it’s empty.
It makes sense, because when another web part is added, the page doesn’t remain a list page anymore and all the list specific options are taken out.
SharePoint Know-how 
#1 by Wayne Collins on May 8, 2012 - 6:04 pm
If you click on the check box next to the attachment column, the list options will appear once more.
#2 by Bill on March 5, 2013 - 10:32 pm
Is there anyway to add a web part and then make the List Tools come back on the Ribbon?
#3 by bgm on July 31, 2013 - 9:59 pm
Is there a fix for this? I’ve a Sharepoint Stack Exchange post here with a pseudo-solution, but not a good solution. http://sharepoint.stackexchange.com/questions/73174/items-and-list-tabs-in-ribbon-dont-show-in-custom-master/74040#74040