git-gui: Fix 'Select All' action on Windows.

Sometimes the Select All action from our context menus doesn't work
unless the text field its supposed to act on has focus.  I'm not
really sure why adding the sel tag requires having focus.  It
technically should not be required to update the sel tag membership,
but perhaps there is a bug in Tcl/Tk 8.4.1 on Windows which is
causing this odd behavior.

Signed-off-by: Shawn O. Pearce <[email protected]>

Author: spearce

git-gui.sh

@@ -2539,7 +2539,7 @@ proc console_init {w} {
 		-command "tk_textCopy $w.m.t"
 	$w.ctxm add command -label "Select All" \
 		-font font_ui \
-		-command "$w.m.t tag add sel 0.0 end"
+		-command "focus $w.m.t;$w.m.t tag add sel 0.0 end"
 	$w.ctxm add command -label "Copy All" \
 		-font font_ui \
 		-command "
@@ -3913,7 +3913,7 @@ $ctxm add separator
 $ctxm add command \
 	-label {Select All} \
 	-font font_ui \
-	-command {$ui_comm tag add sel 0.0 end}
+	-command {focus $ui_comm;$ui_comm tag add sel 0.0 end}
 $ctxm add command \
 	-label {Copy All} \
 	-font font_ui \
@@ -4059,7 +4059,7 @@ lappend diff_actions [list $ctxm entryconf [$ctxm index last] -state]
 $ctxm add command \
 	-label {Select All} \
 	-font font_ui \
-	-command {$ui_diff tag add sel 0.0 end}
+	-command {focus $ui_diff;$ui_diff tag add sel 0.0 end}
 lappend diff_actions [list $ctxm entryconf [$ctxm index last] -state]
 $ctxm add command \
 	-label {Copy All} \