diff --git a/powerline/bindings/bash/powerline.sh b/powerline/bindings/bash/powerline.sh
index 5b2af071..e5295ab3 100644
--- a/powerline/bindings/bash/powerline.sh
+++ b/powerline/bindings/bash/powerline.sh
@@ -16,11 +16,11 @@ _powerline_tmux_setenv() {
 	fi
 }
 
-POWERLINE_SAVED_PWD=
+_POWERLINE_SAVED_PWD=
 
 _powerline_tmux_set_pwd() {
-	if test "x$POWERLINE_SAVED_PWD" != "x$PWD" ; then
-		POWERLINE_SAVED_PWD="$PWD"
+	if test "x$_POWERLINE_SAVED_PWD" != "x$PWD" ; then
+		_POWERLINE_SAVED_PWD="$PWD"
 		_powerline_tmux_setenv PWD "$PWD"
 	fi
 }
diff --git a/powerline/bindings/zsh/powerline.zsh b/powerline/bindings/zsh/powerline.zsh
index 6b55f1c3..21f56740 100644
--- a/powerline/bindings/zsh/powerline.zsh
+++ b/powerline/bindings/zsh/powerline.zsh
@@ -50,9 +50,9 @@ _powerline_setup_prompt() {
 	chpwd_functions+=( _powerline_tmux_set_pwd )
 	_powerline_set_true_keymap_name "${${(Q)${${(z)${"$(bindkey -lL main)"}}[3]}}:-.safe}"
 	if zmodload zsh/zpython &>/dev/null ; then
-		zpython 'from powerline.bindings.zsh import setup as powerline_setup'
-		zpython 'powerline_setup()'
-		zpython 'del powerline_setup'
+		zpython 'from powerline.bindings.zsh import setup as _powerline_setup'
+		zpython '_powerline_setup()'
+		zpython 'del _powerline_setup'
 	else
 		local add_args='--last_exit_code=$? --last_pipe_status="$pipestatus"'
 		add_args+=' --jobnum=$_POWERLINE_JOBNUM'
@@ -70,21 +70,24 @@ _powerline_add_widget() {
 	elif [[ -z "$old_widget_command" ]] ; then
 		zle -N $widget $function
 	else
-		local save_widget="powerline_save_$widget"
+		local save_widget="_powerline_save_$widget"
 		local -i i=0
 		while ! test -z "$(zle -l -L $save_widget)" ; do
 			save_widget="${save_widget}_$i"
 			(( i++ ))
 		done
+		# If widget was defined with `zle -N widget` (without `function` 
+		# argument) then this function will be handy.
+		eval "function $save_widget() { emulate -L zsh; $widget \$@ }"
 		eval "${old_widget_command/$widget/$save_widget}"
 		zle -N $widget $function
-		export POWERLINE_SAVE_WIDGET="$save_widget"
+		export _POWERLINE_SAVE_WIDGET="$save_widget"
 	fi
 }
 
 _powerline_set_true_keymap_name() {
-	export POWERLINE_MODE="${1}"
-	local plm_bk="$(bindkey -lL ${POWERLINE_MODE})"
+	export _POWERLINE_MODE="${1}"
+	local plm_bk="$(bindkey -lL ${_POWERLINE_MODE})"
 	if [[ $plm_bk = 'bindkey -A'* ]] ; then
 		_powerline_set_true_keymap_name ${(Q)${${(z)plm_bk}[3]}}
 	fi
@@ -93,14 +96,14 @@ _powerline_set_true_keymap_name() {
 _powerline_zle_keymap_select() {
 	_powerline_set_true_keymap_name $KEYMAP
 	zle reset-prompt
-	test -z "$POWERLINE_SAVE_WIDGET" || zle $POWERLINE_SAVE_WIDGET
+	test -z "$_POWERLINE_SAVE_WIDGET" || zle $_POWERLINE_SAVE_WIDGET
 }
 
 _powerline_add_widget zle-keymap-select _powerline_zle_keymap_select
 _powerline_precmd
 
-if [[ "$POWERLINE_MODE" != vi* ]] ; then
-	export POWERLINE_DEFAULT_MODE="$POWERLINE_MODE"
+if [[ "$_POWERLINE_MODE" != vi* ]] ; then
+	export _POWERLINE_DEFAULT_MODE="$_POWERLINE_MODE"
 fi
 
 trap "_powerline_tmux_set_columns" SIGWINCH
diff --git a/powerline/segments/shell.py b/powerline/segments/shell.py
index 1245d109..af894ebf 100644
--- a/powerline/segments/shell.py
+++ b/powerline/segments/shell.py
@@ -57,7 +57,7 @@ def mode(pl, segment_info, override={'vicmd': 'COMMND', 'viins': 'INSERT'}, defa
 	'''
 	mode = segment_info['mode']
 	if not mode:
-		pl.warn('No or empty POWERLINE_MODE variable')
+		pl.debug('No or empty POWERLINE_MODE variable')
 		return None
 	default = default or segment_info['environ'].get('POWERLINE_DEFAULT_MODE')
 	if mode == default: