Fix the <Return> binding for tk_dialog to invoke the focused button.

The standard for Windows and Gtk+ is that the <Return> binding invokes
the button that currently has the keyboard focus. This can be seen in
tk_messageBox which implements this.
This patch implements this feature and also makes use of the tk grab
utility functions to replace the  grab handling code.

2 files changed, 13 insertions, 24 deletions

diff --git a/ChangeLog b/ChangeLog
index 0df44f6..67c459d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 2010-01-04  Pat Thoyts  <patthoyts@users.sourceforge.net>
 
+	* library/dialog.tcl: [Bug 2811266] <Return> binding should invoke
+	the button with the focus.
 	* library/fontchooser.tcl: [Bug 2727476] Fix default size of font
 	chooser dialog and assigned minimum sizes for the lists.
 	* library/console.tcl: [Bug 580361] Fix console <<Cut>> binding.
diff --git a/library/dialog.tcl b/library/dialog.tcl
index b032b62..5012823 100644
--- a/library/dialog.tcl
+++ b/library/dialog.tcl
@@ -3,7 +3,7 @@
 # This file defines the procedure tk_dialog, which creates a dialog
 # box containing a bitmap, a message, and one or more buttons.
 #
-# RCS: @(#) $Id: dialog.tcl,v 1.24 2007/12/13 15:26:27 dgp Exp $
+# RCS: @(#) $Id: dialog.tcl,v 1.25 2010/01/04 21:22:08 patthoyts Exp $
 #
 # Copyright (c) 1992-1993 The Regents of the University of California.
 # Copyright (c) 1994-1997 Sun Microsystems, Inc.
@@ -129,15 +129,14 @@ proc ::tk_dialog {w title text bitmap default args} {
 
     # 4. Create a binding for <Return> on the dialog if there is a
     # default button.
+    # Convention also dictates that if the keyboard focus moves among the
+    # the buttons that the <Return> binding affects the button with the focus.
 
     if {$default >= 0} {
-	bind $w <Return> "
-	[list $w.button$default] configure -state active -relief sunken
-	update idletasks
-	after 100
-	set ::tk::Priv(button) $default
-	"
+	bind $w <Return> [list $w.button$default invoke]
     }
+    bind $w <<PrevWindow>> [list bind $w <Return> {[tk_focusPrev %W] invoke}]
+    bind $w <<NextWindow>> [list bind $w <Return> {[tk_focusNext %W] invoke}]
 
     # 5. Create a <Destroy> binding for the window that sets the
     # button variable to -1;  this is needed in case something happens
@@ -172,17 +171,12 @@ proc ::tk_dialog {w title text bitmap default args} {
 
     # 7. Set a grab and claim the focus too.
 
-    set oldFocus [focus]
-    set oldGrab [grab current $w]
-    if {$oldGrab ne ""} {
-	set grabStatus [grab status $oldGrab]
-    }
-    grab $w
     if {$default >= 0} {
-	focus $w.button$default
+        set focus $w.button$default
     } else {
-	focus $w
+        set focus $w
     }
+    tk::SetFocusGrab $w $focus
 
     # 8. Wait for the user to respond, then restore the focus and
     # return the index of the selected button.  Restore the focus
@@ -191,21 +185,14 @@ proc ::tk_dialog {w title text bitmap default args} {
     # restore any grab that was in effect.
 
     vwait ::tk::Priv(button)
-    catch {focus $oldFocus}
+
     catch {
 	# It's possible that the window has already been destroyed,
 	# hence this "catch".  Delete the Destroy handler so that
 	# Priv(button) doesn't get reset by it.
 
 	bind $w <Destroy> {}
-	destroy $w
-    }
-    if {$oldGrab ne ""} {
-	if {$grabStatus ne "global"} {
-	    grab $oldGrab
-	} else {
-	    grab -global $oldGrab
-	}
     }
+    tk::RestoreFocusGrab $w $focus
     return $Priv(button)
 }