On Tue, 14 Sep 1999, Andrew C. Greenberg wrote:

> Here's another one.  Take any browser list panel that needs to be
> scrolled.  Select the top element of the list, and then scroll down
> so that the element is no longer visible.  Return to the top, and the
> element is unhilighted, appearing to be de-selected, though the
> browser otherwise behaves as thought it were selected.
>
> Click on it again, and the line will show as hilighted.  however, the
> browser will behave as though it were deselected.  Then, for maximum
> cognitive dissonance, select another item, and watch both elements
> remain hilighted.
>
> As with the above, this is MVC only.

That one is a relatively serious bug which seems to have crept in sometime
before the 2.5 release.  (2.4 was fine.)  I was using MVC for the first
time in awhile the other day, and I ran into it rather quickly.  Hopefully
someone will take a look at it.  (I'm not as much of an MVC bug fixer
myself.)

I might as well mention a couple of less-serious UI bugs while we're at
it, for the bug archive.  (These bugs are both Morphic only.)

1.  If you click on the topmost pixel of a Morphic ScrollableListMorph, it
will select the last item in the list, not the first.  Not a common error,
but disorienting when it happens.  (To reproduce it, click on the first
category (Kernel-Objects) in the category pane of the system browser.
Repeatedly click it on and off, and inch your mouse up one pixel at a time
until suddenly the Alice2.0-Interface category becomes picked.)

2.  The Morphic (inboard) scrollbar isn't drawn in exactly the right place
after a window/pane resizing.  It's pretty close, but when you grab the
scrollbar afterward, the pane contents can jump by quite a bit.  This bug
precedes my proportional-scrollbar enhancement back in 2.4, so don't blame
me. :-)  (To reproduce it, open a system browser without resizing the
window.  Scroll the category pane down most of the way so that, say,
Balloon-3D-Viewing appears as the uppermost category in the pane.  Then
resize the system browser so that it's twice as tall as it was before.
Now grab the scrollbar square (hold mouse down).  Note that the category
list jumped so that Balloon-3D-Viewing is not at or near the top anymore.)

#1 sounds like a one-line fix somewhere... just a matter of finding it.
#2 is probably trickier... since I'm probably as familiar with the Morphic
scrolling code as anyone, I should probably look at it at some point.

- Doug Way
  dway at mat.net