This problem is happening under OSX 10.11.2 with Aptana Studio 3.6.1 "AS3" After creating a projectFolder and some subfolders with some html/css/js files and did some coding in a different text editor. Started AS3, right click on projectFolder and did Promote to Project, accepted the default with Project Type = Web, edited my.html file and saved it.
In the Project Explorer on my.html, RightClick > Compare With > Local History...
but a pop up window saying "No local history available for selected resource".
Please help me find what I am doing wrong in order to get this functionality to work.