[comp.sys.mac.hypercard] scrolling field bug in HC

BELSLEY%BCVMS.BITNET@MITVMA.MIT.EDU (04/06/88)

Here is a HyperCard (v 1.1) bug I haven't yet seen reported.  Create a
scrolling field and set the text to 9 point Geneva, making the window
heigth, say, 5 lines plus 2 or 3 pixels (do not make it exactly 5 lines).
Now type in some text in each of the first five lines.  Set the cursor at
the end of the text in the last line and hit return 4 or 5 times.  The field
will, of course, scroll downwards, scrolling the text off the top.  Now
backspace (delete) 4 or 5 times to return the cursor to the end of the last
line of text.
  The cursor will rise one line with each backspace, and when it reaches the
text, the scroll box will suddenly rise to the top of the scroll bar.  The
text that had previously scrolled off the top will remain off the top, but,
since the scroll box is at the top, the window can not be scrolled down, and
there is no way, with the scroll bar, to retrieve the text off the top.  If
one closes the window, or selects the text tool, the window will
automatically revert to its zero scroll position, but the scroll bar itself
will have lost control.
  I have only had this happen using 9-point Geneva.  I have not experimented
to see what other configurations would produce the problem.  However, I have
reproduced the 9-point, 5-line situation I just described several times.

david a. belsley
boston college       belsley@bcvax3.bitnet