What is "Default applications for LXSession" in Lubuntu 13.10?

I know this is an old question but it showed up as my first result in a Google search for "lxsession defualt application names" so I thought I might at least post something in case other folks end up here for the same reason.

My version does not have the "Running applications" tab but the "Launching applications" tab is where you specify which program will be used for common tasks (web browsing, checking email, writing documents, etc.). For example, if your keyboard has a button that should open a web browser it is here that you set which browser (Chrome, Firefox, Opera, etc.) it should open.