[MG], on June 8th 2005
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Um, is this reported in the Tk Bug Tracker?
http://sourceforge.net/tracker/?group_id=12997&atid=112997

''[MG] I've just skimmed the list, and can't see it there, no. I'm not entirely sure it is actually a Tk bug, though - we're both running the same OS, and the same version of (Active)Tcl/Tk, but I can't get the problem on my computer, doing exactly the same thing he's doing. I'll do some more testing as suggested below, and see if I can replicate it any other way (either on this computer, or on his outside of this particular Tcl program), and see what I can find out...''

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Hey folks,

A friend of mine using a Tcl/Tk program I wrote ([Potato MUSH (MUD) Client]) seems to have found a bug in the Text widget, but it's one I can't to replicate (I'm using ActiveTcl 8.4.9). The text widget has a few modified bindings, but the only one which could be relevant to this is a new <MouseWheel> binding: 

  bind Text <MouseWheel> {mouseWheel %W %X %Y %D}
  proc mouseWheel {w x y d} {

    set in [winfo containing -displayof $w $x $y]
    if { $in == "" || [winfo class $in] != "Text" } {
         $w yview scroll [expr {- ($d / 120) * 4}] units
       } else {
         $in yview scroll [expr {- ($d / 120) * 4}] units
       }
  };# mouseWheel

When he scrolls with the middle button (a wheel mouse), the display of the Text widget becomes, for lack of a better word, "screwy". A couple of screen shots (before and after scrolling) are below, along with some info on his computer / Tcl version.. if anyone has any ideas, about whether this is a bug in the Text widget or something in my code, I'd appreciate any help.

Mike

''(My apologies for the huge images, btw - I didn't want to shrink them for risk of losing clarity)''
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''[escargo] 8 Jun 2005'' - Maybe you could build a test version and use [event generate] to simulate
mousewheel movement and see if you can duplicate the problem.

[MG] Yeah, that's a good idea - can't think why it never occurred to me, now that you've said it :) I'll do some experimenting and see what I can find... There isn't a way to bind to any and all events, is there? I know you can, for instance, bind to <Key> for all keypress events, but I don't know of a catch-all binding (for the purposes of ''bind $textWidget <All> {puts %K}'' to see exactly what's firing).
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 % set tcl_patchLevel
 8.4.9
 % set tk_patchLevel
 8.4.9
 % parray tcl_platform
 tcl_platform(byteOrder) = littleEndian
 tcl_platform(machine)   = intel
 tcl_platform(os)        = Windows NT
 tcl_platform(osVersion) = 5.1
 tcl_platform(platform)  = windows
 tcl_platform(user)      = The Master
 tcl_platform(wordSize)  = 4

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Before: 

[http://www.talvo.com/textwidget/bugtst1.jpg]


And after:

[http://www.talvo.com/textwidget/bugtst2.jpg]

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[Peter Newman] 9 June 2005: From the ''bind'' manpage:-

   * %X - The x_root field from the event. If a virtual-root window manager is being used then the substituted value is the corresponding x-coordinate in the virtual root. Valid only for '''ButtonPress''', '''ButtonRelease''', '''KeyPress''', '''KeyRelease''', and '''Motion''' events. 
   * %Y - The y_root field from the event. If a virtual-root window manager is being used then the substituted value is the corresponding y-coordinate in the virtual root. Valid only for '''ButtonPress''', '''ButtonRelease''', '''KeyPress''', '''KeyRelease''', and '''Motion''' events. 

Doesn't this mean that ''%X'' and ''%Y'' aren't supported by the ''MouseWheel'' event?