Operating system and graphics card
Windows 7, Intel Integrated
Broken: (example: 2.69.7 4b206af, see splash screen)
(I'm nearly certain this worked fine in 2.69)
Short description of error
The handles on Keyframes in the Graph Editor along the x-axis cannot be Scaled (stretched) along the x-axis. In the past, you could go to an individual frame, highlight, for instance, the LocRotScale frames, and then go S > X, and those bezier handles would all stretch out. Now, they do not budge.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
(1) Select the default cube
(2) On frame 1, Keyframe the LocRotScale
(3) On frame 20, move the default cube and again Keyframe the LocRotScale
(4) Go to the Graph Editor and highlight the Keyframes on frame #20. To try and make the animation slower, go S > X to stretch the handles out. They will not budge.
(As a note: This has a MAJOR impact on my personal Keyframing - and so I would guess on that of many other users, too. Very often, when I'd want to just make the animation a bit slower, I'd stretch them out. Or, if I wanted a jarring start or end to an animation, I'd just go S > X > 0. Now, none of that is possible, and every single Keyframe has to be moved manually. This is VERY time-consuming and also imprecise.)