HyperCard 2.2: Screen Doesn‘t Refresh Color When Scrolling

If a color object is in a scrollable window, and the window is then
scrolled, the area scrolled onto the screen will be white. This is
because the stack is not refreshing itself properly during the scroll.
It is possible to program around this.

In the OpenStack handler (or any setup handler) check the visible of
the scroll window to see if refresh routines are necessary:

on (some action)
global needsRefresh
if the visible of window "scroll" then put true into needsRefresh
end (some action)

Then any other handler could periodically call a refresh handler:

on idle -- or whatever
refreshScreen
end idle

on refreshScreen
global needsRefresh
if needsRefresh then go this card
end refreshScreen

Published Date: Feb 19, 2012