I noticed that when taking my foot off the accelerator and coasting, the hybrid display indicates a bar to the left, as it does when braking, although to a lesser extent. Is this normal? I thought that the battery gets charged just on braking....
Mobius, If you have removed your foot from the accelerator pedal, the vehicle will begin to regenerate electricity. While coasting, there will be some wind-down (as with any vehicle). Light application of the brake pedal will increase this effect. Having said that, there is something I've seen referred to as pulse-and-glide. It seems to be a hypermiling technique unique to the Prius whereby one accelerates to speed and then, on a level surface, applies just enough pressure to the gas pedal to disable any regenerative braking, but not enough to request motive force from the electric motor. This is indicated on the screen by a complete absence of any arrows whatsoever whilst moving. I have never seen it personally, but I'm not much of a hypermiler. So -- to answer your original question: Yes. It's normal.
When you step on the brakes, the big traction motor turns into the capture device. You do indeed get electricity regenerated that way. There's also a smaller motor. That's the one at play when you haven't stepped on the brake yet. It's what generates electricity as you drive. Normally, that energy comes from the engine. But when slowing, it can come from the road instead... which is what you were seeing. .
Note that in N, you really are coasting, and no regen is taking place. While I would prefer that that be the same as lifting off the gas pedal, the default of regen is more 'normal' for folks used to any other car.
The small amount of regenerative braking that occurs when you lift your foot from the accelerator pedal is intentional. It mimics the engine drag found in normal cars. Toyota engineers have endeavored to make the Prius feel and drive as much like a normal car as possible. Tom