double mouseDown

[Colin Holgate]

Ok, I've worked out your script, and the problem is that the hot spot  
is only one pixel wide, and it's the pixel that is four pixels to the  
left of where the line is located. Once you click and hold there the  
hand cursor does appear, but dragging doesn't show a live update.

The reason the column collapses is because your value tabWidth is zero  
when you do the line after the repeat while the mouse is down loop (if  
the user is double clicking at the time, because the repeat loop  
doesn't see the mouse as being down). Adding this line before the  
repeat would solve the double click issue:

   put item 1 of the mouseloc + hscroll of target into tabWidth
   repeat while the mouse is down
       set the cursor to hand
       put item 1 of the mouseloc + hscroll of target into tabWidth
   end repeat

But you would still get another strangeness, because of the four pixel  
offset. The column divider would jump those four pixels to the left if  
you did double click.

Ideally, you should have the hot spot be exactly on target, and it  
would be nice if it was possible to set the cursor to hand on  
mousewithin as well, but that seems not to work.