Below is a list of the bugs that are fixed by patch 3 for Tk 4.0
(Tk 4.0p3):

9/22/95 (bug fix) Fixed bug where text widgets could occasionally
display the insertion cursor both at the end of one line and the
beginning of the next. (JO)

9/25/95 (bug fix) Text widgets sometimes scrolled backwards on
occasion if you dragged down past the bottom of the scrollbar. (JO)

9/25/95 (bug fix) Fixed bug in menus where a cascaded submenu posted
from a torn-off menu could be left posted if mouse was pulled off the
end of the cascade and released. (JO)

9/25/95 (new feature) Added "--" switch to wish, so that you can
pass arguments like -n through to a script without having wish
interpret them. (JO)

9/25/95 (bug fix) Fixed core dump that could occur for radiobuttons
and selectbuttons if -selectcolor was an empty string. (JO)

9/26/95 (bug fix) Entries didn't used to notice if a trace procedure
on the -textvariable overrode a new value set by the entry.  This
could cause the variable to get out of sync with the contents of the
entry. (JO)

9/26/95 (bug fix) Fixed round-off errors in listbox scrolling.  Among
other things, this could cause listbox view to shift slightly at
unexpected times. (JO)

9/26/95 (bug fix) TkColor.c wasn't computing colormap size correctly;
could result in X Protocol error for QueryColors when colormaps run
out of colors. (JO)

9/27/95 (feature change)  Modified tk_dialog so that it uses the
option database for the -wraplength option on the message.  This
allows the option to be overridden by the caller. (JO)

10/1/95 (bug fix) Canvas rectangles weren't computing their bounding
boxes correctly when coordinates were negative, resulting in improper
redisplay (e.g. junk left behind) when dragging. (JO)

10/30/95 (bug fix) When focus-follows-mode (invoked via tk_focusFollowsMouse),
was focussing on windows even in situations where keyboard traversal would
skip the window.  Changed to use the tkFocusOK procedure so that the
criteria for focussing are the same in both modes. (JO)

11/2/95 (bug fix) Changed listbox bindings to ignore double-clicks.
This avoids errors that used to occur if a user defined a binding
for double-click that deleted the listbox. (JO)

11/7/95 (bug fix) If wish was invoked with a command-line geometry and
a script file (e.g. "wish foo.tcl -geometry 30x20"), and if one of
the windows created by the script used the -setgrid option, then the
width and height from the command line were lost. (JO)

11/8/95 (bug fix) The "see" command didn't work quite right for texts:
if the window was small and you try to "see" a line just offscreen,
Tk centered the line (actually, mis-centered it) when it should have
aligned it at the top or bottom. (JO)

11/9/95 (bug fix) The "send" command crashed if you tried to send to
a different display with "-displayof". (JO)

11/9/95 (bug fix) The Symbol font didn't print right in Postscript
output, because of changes made to re-encode fonts to get proper
ISO Latin1 behavior.  Changed the code not to re-encode the Symbol
font. (JO)

11/17/95 (bug fix) If a window was gridded, Tk still computed the
default maximum dimensions in pixel units, which resulted in windows
that could grow much larger than the screen. (JO)

11/17/95 (bug fix) If a menus entries were all disabled, posting
the menu and typing Up or Down caused an infinite loop, locking
up the screen (JO).

11/19/95 (bug fix) The focus wasn't being restored properly after a
menu selection in a cascaded menu. (JO)

11/19/95 (bug fix) Menubutton's didn't stipple display their images
differently when disabled.  Change to have the same behavior as buttons:
the image is stippled over in the background color when the menubutton
is disabled. (JO)

11/21/95 (bug fix) Changes in display attributes such as font could
cause core dumps in the text widget under some circumstances involving
line wrapping. (JO)

11/22/95 (bug fix/new feature)  Changed both the placer and the packer
to ensure that slaves are unmapped whenever the master is unmapped.
This saves time that slaves might otherwise spend trying to redisplay
themselves when they're unmapped. (JO)

11/22/95 (bug fix) Space and return keys didn't work for menus if
they were posted via Alt-x keystrokes. (JO)

11/24/95 (bug fix) tk_dialog procedure had binding for <Return> that
always activated default binding, even if input focus was in some
other binding.  Removed this feature, since existing focus support
will already "do the right thing".  (JO)

11/24/95 (bug fix) Both canvases and texts could dump core if a binding
(such as ButtonRelease on an internal item) deleted the widget. (JO)

11/24/95 (bug fix) It was possible for a slave to be placed or packed
-in itself, with unpleasant consequences.  It is now an error for the
slave to be its own master for geometry management. (JO)

11/25/95 (bug fix) The -command option of scales was sometimes being
invoked spuriously (e.g. when the mouse moved in the scale without a
button down).  This was because the scale wasn't rounding properly
when setting the scale value from its associated variable. (JO)