>I've written a couple of classes that display histograms inside a
>standard system view. Everything seems to be working except that the
>view isn't redrawn when it's exposed by another window moving. It
>seems like I must be missing something simple. Any hints?

Chose "windows..." from the main display menu and turn on "don't save 
bits (compact)".  If everything then works as you expect, the problem is 
that your histogram window is drawn in color, and you should be using a 
ColorSystemView for the top level, instead of a StandardSystemView.  The 
StandardSystemView assumes that a window is "two-tone", with a single 
background color and a black foreground.  When a StandardSystemView is 
displayed, its bits are cached in a 1-bit deep ColorForm (see 
ColorForm>>twoToneFromDisplay...).  This works great for the standard 
text windows, and saves a lot of space, but doesn't work well for other 
views.  A ColorSystemView caches the view directly from the Display at 
the full Display depth.  Try changing the top level view to a 
ColorSystemView, and change the window caching policy back to "save bits 
(fast)", and see if everything works as expected.

>More generally: I was also wondering if there's any documents on
>smalltalk-80 MVC stuff I could read. I've got some idea of what's
>going through reading the code for existing stuff, and looking at
>"Smalltalk-80 : Interactive Programming Environment" but but I don't
>really have a good firm of what's going on, especially with
>controllers. 

<http://st-www.cs.uiuc.edu/users/smarch/st-docs/mvc.html>
Has some basic info about using the MVC model.




     -- tim