Allow keyboard control to work in the staging widgets.

Keyboard focus was restricted to the commit message widget and users were
forced to use the mouse to select files in the workdir widget and only then
could use a key combination to stage the file.
It is now possible to use key navigation (Ctrl-Tab, arrow keys and Ctrl-T
or Ctrl-U) to stage and unstage files.
Suggested by @koppor in git-for-window/git issue #859

Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>

git-gui.sh

@@ -2505,13 +2505,28 @@ proc force_first_diff {after} {
 	}
 }
 
-proc toggle_or_diff {w x y} {
+proc toggle_or_diff {mode w args} {
 	global file_states file_lists current_diff_path ui_index ui_workdir
 	global last_clicked selected_paths
 
+	if {$mode eq "click"} {
+		foreach {x y} $args break
 		set pos [split [$w index @$x,$y] .]
-	set lno [lindex $pos 0]
+		foreach {lno col} $pos break
-	set col [lindex $pos 1]
+	} else {
+		if {$last_clicked ne {}} {
+			set lno [lindex $last_clicked 1]
+		} else {
+			set lno [expr {int([lindex [$w tag ranges in_diff] 0])}]
+		}
+		if {$mode eq "toggle"} {
+			set col 0; set y 2
+		} else {
+			incr lno [expr {$mode eq "up" ? -1 : 1}]
+			set col 1
+		}
+	}
+
 	set path [lindex $file_lists($w) [expr {$lno - 1}]]
 	if {$path eq {}} {
 		set last_clicked {}
@@ -2519,6 +2534,7 @@ proc toggle_or_diff {w x y} {
 	}
 
 	set last_clicked [list $w $lno]
+	focus $w
 	array unset selected_paths
 	$ui_index tag remove in_sel 0.0 end
 	$ui_workdir tag remove in_sel 0.0 end
@@ -2598,7 +2614,7 @@ proc add_range_to_selection {w x y} {
 	global file_lists last_clicked selected_paths
 
 	if {[lindex $last_clicked 0] ne $w} {
-		toggle_or_diff $w $x $y
+		toggle_or_diff click $w $x $y
 		return
 	}
 
@@ -3188,6 +3204,7 @@ text $ui_index -background white -foreground black \
 	-borderwidth 0 \
 	-width 20 -height 10 \
 	-wrap none \
+	-takefocus 1 -highlightthickness 1\
 	-cursor $cursor_ptr \
 	-xscrollcommand {.vpane.files.index.sx set} \
 	-yscrollcommand {.vpane.files.index.sy set} \
@@ -3208,6 +3225,7 @@ text $ui_workdir -background white -foreground black \
 	-borderwidth 0 \
 	-width 20 -height 10 \
 	-wrap none \
+	-takefocus 1 -highlightthickness 1\
 	-cursor $cursor_ptr \
 	-xscrollcommand {.vpane.files.workdir.sx set} \
 	-yscrollcommand {.vpane.files.workdir.sy set} \
@@ -3815,10 +3833,10 @@ bind .   <$M1B-Key-r> ui_do_rescan
 bind .   <$M1B-Key-R> ui_do_rescan
 bind .   <$M1B-Key-s> do_signoff
 bind .   <$M1B-Key-S> do_signoff
-bind .   <$M1B-Key-t> do_add_selection
+bind .   <$M1B-Key-t> { toggle_or_diff toggle %W }
-bind .   <$M1B-Key-T> do_add_selection
+bind .   <$M1B-Key-T> { toggle_or_diff toggle %W }
-bind .   <$M1B-Key-u> do_unstage_selection
+bind .   <$M1B-Key-u> { toggle_or_diff toggle %W }
-bind .   <$M1B-Key-U> do_unstage_selection
+bind .   <$M1B-Key-U> { toggle_or_diff toggle %W }
 bind .   <$M1B-Key-j> do_revert_selection
 bind .   <$M1B-Key-J> do_revert_selection
 bind .   <$M1B-Key-i> do_add_all
@@ -3830,9 +3848,11 @@ bind .   <$M1B-Key-plus> {show_more_context;break}
 bind .   <$M1B-Key-KP_Add> {show_more_context;break}
 bind .   <$M1B-Key-Return> do_commit
 foreach i [list $ui_index $ui_workdir] {
-	bind $i <Button-1>       "toggle_or_diff         $i %x %y; break"
+	bind $i <Button-1>       { toggle_or_diff click %W %x %y; break }
-	bind $i <$M1B-Button-1>  "add_one_to_selection   $i %x %y; break"
+	bind $i <$M1B-Button-1>  { add_one_to_selection %W %x %y; break }
-	bind $i <Shift-Button-1> "add_range_to_selection $i %x %y; break"
+	bind $i <Shift-Button-1> { add_range_to_selection %W %x %y; break }
+	bind $i <Key-Up>         { toggle_or_diff up %W; break }
+	bind $i <Key-Down>       { toggle_or_diff down %W; break }
 }
 unset i