This is useful to know. There is a bug in the 'interactive split tool' that replaced the 'split polygon tool' in 2012. Sometimes it completely stops working and crashes your scene. I haven't found a fix to get the 'interactive split tool' working again once it stops but there is a workaround.
Select your mesh, press 'shift' on your keyboard, right click mouse, select 'split' from the menu and you will find the original 'split polygon tool' which you can use instead.