---Bugs---
	Why doesn't drag-and-drop on the icon work the same as dropping on the
		open view? (e.g., multiple volumes don't work; floppy isn't accepted.)

---Notes---
	Remember to change the alpha component of RGB colors to 0xff with
		DiskProbe, if you use Resourcer.  They live in block 6.

---Future/maybe/bloat---
	Display unavailable files in a distinct color (maybe gray)?
	Find a way to do redrawing more efficiently (BPicture?)
	Add <- and -> buttons to traverse the zoom history.
	Display pie in grayscale+patterns / color?
	Display an icon somewhere while volumes are being scanned.  Check out the
		barber shop icon in the Tracker during queries!
	Handle the special case where the volume is full: the volume display is
		the same as the root directory display except for the colors!
	When scanning all volumes, scan different physical devices in parallel,
		and multiple partitions on a device in sequence.
	Add a cancel button during scanning?
	A button to cycle colors?  (Useless toy).