diff --git a/powerline/bindings/bash/powerline.sh b/powerline/bindings/bash/powerline.sh
index 50eb4878..ba33e2aa 100644
--- a/powerline/bindings/bash/powerline.sh
+++ b/powerline/bindings/bash/powerline.sh
@@ -1,11 +1,17 @@
 _powerline_tmux_setenv() {
 	if [[ -n "$TMUX" ]]; then
-		tmux setenv TMUX_"$1"_$(tmux display -p "#D" | tr -d %) "$2"
+		tmux setenv -g TMUX_"$1"_$(tmux display -p "#D" | tr -d %) "$2"
+		tmux refresh -S
 	fi
 }
 
+POWERLINE_SAVED_PWD=
+
 _powerline_tmux_set_pwd() {
-	_powerline_tmux_setenv PWD "$PWD"
+	if test "x$POWERLINE_SAVED_PWD" != "x$PWD" ; then
+		POWERLINE_SAVED_PWD="$PWD"
+		_powerline_tmux_setenv PWD "$PWD"
+	fi
 }
 
 _powerline_tmux_set_columns() {
@@ -18,6 +24,7 @@ _powerline_prompt() {
 		eval $POWERLINE_OLD_PROMPT_COMMAND
 	PS1="$(powerline shell left -r bash_prompt --last_exit_code=$last_exit_code)"
 	_powerline_tmux_set_pwd
+	return $last_exit_code
 }
 
 trap "_powerline_tmux_set_columns" SIGWINCH
diff --git a/powerline/bindings/tmux/powerline.conf b/powerline/bindings/tmux/powerline.conf
index 5d43cd37..5951848c 100644
--- a/powerline/bindings/tmux/powerline.conf
+++ b/powerline/bindings/tmux/powerline.conf
@@ -5,7 +5,7 @@ set -g status-fg colour231
 set -g status-bg colour234
 set -g status-left-length 20
 set -g status-left '#[fg=colour16,bg=colour254,bold] #S #[fg=colour254,bg=colour234,nobold]#(powerline tmux left)'
-set -g status-right '#(powerline tmux right)'
+set -g status-right '#(powerline tmux right -R pane_id=`tmux display -p "#D"`)'
 set -g status-right-length 150
 set -g window-status-format "#[fg=colour244,bg=colour234]#I #[fg=colour240] #[fg=colour249]#W "
 set -g window-status-current-format "#[fg=colour234,bg=colour31]#[fg=colour117,bg=colour31] #I  #[fg=colour231,bold]#W #[fg=colour31,bg=colour234,nobold]"
diff --git a/powerline/bindings/zsh/powerline.zsh b/powerline/bindings/zsh/powerline.zsh
index a45a6657..301bc411 100644
--- a/powerline/bindings/zsh/powerline.zsh
+++ b/powerline/bindings/zsh/powerline.zsh
@@ -1,7 +1,8 @@
 _powerline_tmux_setenv() {
 	emulate -L zsh
 	if [[ -n "$TMUX" ]]; then
-		tmux setenv TMUX_"$1"_$(tmux display -p "#D" | tr -d %) "$2"
+		tmux setenv -g TMUX_"$1"_$(tmux display -p "#D" | tr -d %) "$2"
+		tmux refresh -S
 	fi
 }
 
diff --git a/powerline/lib/__init__.py b/powerline/lib/__init__.py
index 8f6a7ba2..f8d831ac 100644
--- a/powerline/lib/__init__.py
+++ b/powerline/lib/__init__.py
@@ -44,7 +44,11 @@ def keyvaluesplit(s):
 		raise ValueError('Option names must not start with `_\'')
 	idx = s.index('=')
 	o = s[:idx]
-	val = json.loads(s[idx + 1:])
+	rest = s[idx + 1:]
+	if rest[0] in '"{[0193456789' or rest in ('null', 'true', 'false'):
+		val = json.loads(s[idx + 1:])
+	else:
+		val = rest
 	return (o, val)
 
 
diff --git a/powerline/renderers/tmux.py b/powerline/renderers/tmux.py
index 34e4329e..19ac3fed 100644
--- a/powerline/renderers/tmux.py
+++ b/powerline/renderers/tmux.py
@@ -40,5 +40,17 @@ class TmuxRenderer(Renderer):
 					tmux_attr += ['nounderscore']
 		return '#[' + ','.join(tmux_attr) + ']'
 
+	def get_segment_info(self, segment_info):
+		r = self.segment_info.copy()
+		if segment_info:
+			r.update(segment_info)
+		if 'pane_id' in r:
+			print r['pane_id']
+			print sorted(r['environ'].keys())
+			varname = 'TMUX_PWD_' + r['pane_id'].lstrip('%')
+			if varname in r['environ']:
+				r['getcwd'] = lambda: r['environ'][varname]
+		return r
+
 
 renderer = TmuxRenderer
diff --git a/powerline/shell.py b/powerline/shell.py
index 2ff2c9e4..8b9e8045 100644
--- a/powerline/shell.py
+++ b/powerline/shell.py
@@ -53,6 +53,7 @@ def get_argparser(parser=None, *args, **kwargs):
 	p.add_argument('-c', '--config', metavar='KEY.KEY=VALUE', action='append')
 	p.add_argument('-t', '--theme_option', metavar='THEME.KEY.KEY=VALUE', action='append')
 	p.add_argument('-p', '--config_path', metavar='PATH')
+	p.add_argument('-R', '--renderer_arg', metavar='KEY="VAL"', type=lambda a: dict([parsedotval(a)]))
 	return p
 
 
diff --git a/scripts/powerline b/scripts/powerline
index c4e8b0aa..264f1794 100755
--- a/scripts/powerline
+++ b/scripts/powerline
@@ -15,10 +15,13 @@ if __name__ == '__main__':
 	args = get_argparser(description=__doc__).parse_args()
 	finish_args(args)
 	powerline = ShellPowerline(args, run_once=True)
+	segment_info = {'args': args, 'environ': os.environ},
+	if args.renderer_arg:
+		segment_info.update(args.renderer_arg)
 	rendered = powerline.render(
 		width=args.width,
 		side=args.side,
-		segment_info={'args': args, 'environ': os.environ},
+		segment_info=segment_info,
 	)
 	try:
 		sys.stdout.write(rendered)