picture-mode <-> event-modifiers in subr.el

[xr]

Hi!

I am a user of CUA-mode, which is unfortunatelly not part of the main
distribution.
I think I have found a bug in emacs, which manifests itself using that
package.
the problem is not in that package, however:

the problem situation is the following:
- turn on picture-mode in a buffer
from now on, selection with SHIFT keys do not work!!!
I need to exit emacs and start it again if I want selection.
the selection mechanism works differently in CUA-mode than in
pc-selection-mode so the latter is not affected (but I do not use that).

I have looked into the problem, but have not found the source in
    picture.el.

all I knew is:
somehow the event-modifiers function in subr.el gets screwed up.
more precisely the events lose the event-symbol-elements property, thus
cua-mode is unable to check if shift is among the modifiers.
not all events are affected however: the control-shift-<cursor> keys
seem to still have that property, so they can be broken up by
event-modifiers, however S-<cursor> events are all affected:
(get 'S-up 'event-symbol-elements)    returns (S-up)
(get 'C-S-up 'event-symbol-elements)    returns (up control shift)


and finally the emacs version[s]:
GNU Emacs 20.7.1 (i386-*-nt4.0.1381) of Tue Jun 13 2000 on buffy
I have tried it on my home computer also, it has a redhat compiled
version (which is also 20.7.1).

best regards,
-fkr

PS.:
please drop me a line, if you know what the problem is/you can confirm
the problem is valid.

I have just checked: it is enough to
    M-x load-library picture
to have this side-effect.