[plt-scheme] Multi-line message% ?

> I'm trying to design a standard alert box, but I don't get the
> message text to wrap properly. [...] Is there a way to have
> multi-line messages without using text%? (text% fields have a
> different background on OS X which doesn't look good in an alert
> box.)

The `message-box/custom' in 202.1 doesn't quite solve this problem,
either. It uses something like a text-field% to show long messages.

I plan to work on that in the future, probably by having
`message-box/custom' menually break a long message string into multiple
message%s.

Matthew