RE: Fix some tooltip related problems

[Drew Adams]

> Also, this discussion assumes that we need to hide, or modify the
> appearance of, the tooltip *because* the actions it describes are
> unavailable. How could we change the behavior so that they would be
> available even if the window is the only one in its frame?

Yes, I considered that.  Clearly, for the more specific
question about _this_ tooltip, providing different
actions in the sole-window case might be a reasonable
approach.

But that doesn't address the more general question of
describing generally-but-not-currently-available actions.
Regardless of whether alternative actions can be found
in this or that case, the question of dimmed-tooltip
usefulness remains.