Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!bloom-beacon!BBN.COM!jpool
From: jpool@BBN.COM (Jeremy Pool)
Newsgroups: comp.windows.x
Subject: Accelerators
Message-ID: <8905042357.AA04897@expo.lcs.mit.edu>
Date: 4 May 89 22:14:08 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 33

A few months back Ralph Swick posted an instructional example of how to use
accelerators.  The example was a modification to x11r3/examples/Xaw/xboxes.c,
and showed how to attach Ctrl-c as an accelerator to the "quit" button of
this sample Xaw program.  The modification was real simple:  Just add:

        XtInstallAccelerators(toplevel, q);     /* q = the quit PushButton */

prior to realizing the widget hierarchy, and adding:

        Demo*quit.accelerators: Ctrl<Key>c: set() notify()

to your resources.

I have found two problems in trying to repeat, and modify, this example.

1) I was able to get the accelerator to work only if I installed it on the
   top-most box widget in the widget hierarchy, but not if I installed it
   on toplevel (as shown) or on the viewport which is toplevel's child and
   the box widget's parent.  I can't figure out any obvious reason for
   this, as I would have expected the keyboard event to have been passed
   up the hierarchy, even to toplevel, until it found a widget with a
   translation for this event.  Am I missing something here?

2) An installed accelerator works even when the source widget is
   insensitive.  The Intrinsics documentation doesn't appear to address
   this issue, but the behavior displayed (at least by the MIT Intrinsics
   implementation) seems counterintuitive.  If a button is insensitive,
   and therefore not dispatching to action procedures, wouldn't you expect
   not to be able to dispatch to those same action procedures via an
   accelerator?  Must I put an extra check into all widget action
   procedures, to check for widget sensitivity?

-- Jeremy Pool (jpool@bbn.com)