Since upgrading to OS X Yosemite I have been experiencing this sporadic issue where I suddenly lose the ability to scroll up/down in terminal using my trackpad. Scrolling on the trackpad will instead cycle through all of my previous commands.
I've read about this behavior with vi in Yosemite, but I've not been able to use any of the fixes that they have mentioned (e.g. holding Shift and then scrolling).
Is there a way to get around this or switch between different modes? It is incredibly irritating when it happens.