diff --git a/defaults.lua b/defaults.lua
index 396bf842e..1893c6876 100644
--- a/defaults.lua
+++ b/defaults.lua
@@ -34,6 +34,10 @@ DCREREADER_VIEW_MODE = "page"
 -- default to false
 DSHOWOVERLAP = false
 
+-- show hidden files in filemanager
+-- default to false
+DSHOWHIDDENFILES = false
+
 -- koptreader config defaults
 DKOPTREADER_CONFIG_FONT_SIZE = 1.0		-- range from 0.1 to 3.0
 DKOPTREADER_CONFIG_TEXT_WRAP = 0		-- 1 = on, 0 = off
@@ -52,9 +56,9 @@ DKOPTREADER_CONFIG_CONTRAST = 1.0		-- range from 0.2 to 2.0
 DKOPTREADER_CONFIG_WORD_SAPCINGS = {0.05, 0.15, 0.375}  -- range from 0.05 to 0.5
 DKOPTREADER_CONFIG_DEFAULT_WORD_SAPCING = 0.15			-- range from 0.05 to 0.5
 -- document languages for OCR
-DKOPTREADER_CONFIG_DOC_LANGS_TEXT = {"English", "Chinese_S", "Chinese_T"}
-DKOPTREADER_CONFIG_DOC_LANGS_CODE = {"eng", "chi_sim", "chi_tra"}  -- ISO 639-3 language string, 
-DKOPTREADER_CONFIG_DOC_DEFAULT_LANG_CODE = "eng"  -- and make sure you have corresponding training data 
+DKOPTREADER_CONFIG_DOC_LANGS_TEXT = {"English", "Chinese"}
+DKOPTREADER_CONFIG_DOC_LANGS_CODE = {"eng", "chi_sim"}	-- language code, make sure you have corresponding training data
+DKOPTREADER_CONFIG_DOC_DEFAULT_LANG_CODE = "eng"  		-- that have filenames starting with the language codes
 
 -- gesture detector defaults
 DGESDETECT_DISABLE_DOUBLE_TAP = true
diff --git a/frontend/dbg.lua b/frontend/dbg.lua
index 3d373685b..d87b6f299 100644
--- a/frontend/dbg.lua
+++ b/frontend/dbg.lua
@@ -36,3 +36,6 @@ function LvDEBUG(lv, ...)
 	print("#"..line)
 end
 
+function DEBUGBT()
+	DEBUG(debug.traceback())
+end
diff --git a/frontend/document/document.lua b/frontend/document/document.lua
index 917124ef7..eeadb287f 100644
--- a/frontend/document/document.lua
+++ b/frontend/document/document.lua
@@ -28,6 +28,14 @@ function DocumentRegistry:openDocument(file)
     end
 end
 
+TileCacheItem = CacheItem:new{}
+
+function TileCacheItem:onFree()
+	if self.bb.free then
+		DEBUG("free blitbuffer", self.bb)
+		self.bb:free()
+	end
+end
 
 --[[
 This is an abstract interface to a document
@@ -216,7 +224,7 @@ function Document:renderPage(pageno, rect, zoom, rotation, gamma, render_mode)
 	end
 
 	-- prepare cache item with contained blitbuffer	
-	local tile = CacheItem:new{
+	local tile = TileCacheItem:new{
 		size = size.w * size.h / 2 + 64, -- estimation
 		excerpt = size,
 		pageno = pageno,
@@ -296,7 +304,6 @@ function Document:getPageText(pageno)
 	return text
 end
 
-
 -- load implementations:
 
 require "document/pdfdocument"
diff --git a/frontend/document/koptinterface.lua b/frontend/document/koptinterface.lua
index eb8fab15d..51a03ca3d 100644
--- a/frontend/document/koptinterface.lua
+++ b/frontend/document/koptinterface.lua
@@ -100,7 +100,7 @@ end
 --[[
 auto detect bbox
 --]]
-function KoptInterface:getAutoBBox(doc, pageno)
+function KoptInterface:getAutoBBox(doc, pageno)	
 	local native_size = Document.getNativePageDimensions(doc, pageno)
 	local bbox = {
 		x0 = 0, y0 = 0,
@@ -113,8 +113,9 @@ function KoptInterface:getAutoBBox(doc, pageno)
 	if not cached then
 		local page = doc._document:openPage(pageno)
 		local kc = self:createContext(doc, pageno, bbox)
+		--DEBUGBT()
 		bbox.x0, bbox.y0, bbox.x1, bbox.y1 = page:getAutoBBox(kc)
-		DEBUG("Auto detected bbox", bbox)
+		--DEBUG("Auto detected bbox", bbox)
 		Cache:insert(hash, CacheItem:new{ autobbox = bbox })
 		page:close()
 		kc:free()
@@ -212,6 +213,8 @@ function KoptInterface:getRFPageDimensions(doc, pageno, zoom, rotation)
 end
 
 function KoptInterface:renderPage(doc, pageno, rect, zoom, rotation, gamma, render_mode)
+	--DEBUG("log memory usage at renderPage")
+	--self:logMemoryUsage(pageno)
 	if doc.configurable.text_wrap == 1 then
 		return self:renderreflowedPage(doc, pageno, rect, zoom, rotation, render_mode)
 	else
@@ -240,7 +243,7 @@ function KoptInterface:renderreflowedPage(doc, pageno, rect, zoom, rotation, ren
 		end
 		local page = doc._document:openPage(pageno)
 		-- prepare cache item with contained blitbuffer
-		local tile = CacheItem:new{
+		local tile = TileCacheItem:new{
 			size = fullwidth * fullheight / 2 + 64, -- estimation
 			excerpt = Geom:new{ w = fullwidth, h = fullheight },
 			pageno = pageno,
@@ -604,7 +607,6 @@ end
 get word and word box from position in native page
 ]]--
 function KoptInterface:getWordFromNativePosition(doc, boxes, pos)
-	DEBUG("boxes", boxes)
 	local native_word_box = self:getWordFromBoxes(boxes, pos)
 	local word_box = {
 		word = native_word_box.word,
@@ -726,7 +728,7 @@ end
 helper functions
 --]]
 function KoptInterface:logReflowDuration(pageno, dur)
-	local file = io.open("reflowlog.txt", "a+")
+	local file = io.open("reflow_dur_log.txt", "a+")
 	if file then
 		if file:seek("end") == 0 then -- write the header only once
 			file:write("PAGE\tDUR\n")
@@ -735,3 +737,25 @@ function KoptInterface:logReflowDuration(pageno, dur)
 		file:close()
 	end
 end
+
+function KoptInterface:logMemoryUsage(pageno)
+	local status_file = io.open("/proc/self/status", "r")
+	local log_file = io.open("reflow_mem_log.txt", "a+")
+	local data = -1
+	if status_file then
+		for line in status_file:lines() do
+			local s, n
+			s, n = line:gsub("VmData:%s-(%d+) kB", "%1")
+			if n ~= 0 then data = tonumber(s) end
+			if data ~= -1 then break end
+		end
+		status_file:close()
+	end
+	if log_file then
+		if log_file:seek("end") == 0 then -- write the header only once
+			log_file:write("PAGE\tMEM\n")
+		end
+		log_file:write(string.format("%s\t%s\n", pageno, data))
+		log_file:close()
+	end
+end
diff --git a/frontend/ui/data/koptoptions.lua b/frontend/ui/data/koptoptions.lua
index db93869ff..dd4f0a775 100644
--- a/frontend/ui/data/koptoptions.lua
+++ b/frontend/ui/data/koptoptions.lua
@@ -24,6 +24,7 @@ KoptOptions = {
 			{
 				name = "trim_page",
 				name_text = PAGE_CROP_STR,
+				width = 225,
 				toggle = {MANUAL_STR, AUTO_STR, SEMIAUTO_STR},
 				alternate = false,
 				values = {0, 1, 2},
@@ -187,7 +188,7 @@ KoptOptions = {
 				name = "defect_size",
 				name_text = DEFECT_SIZE_STR,
 				toggle = {SMALL_STR, MEDIUM_STR, LARGE_STR},
-				values = {1.0, 8.0, 15.0},
+				values = {1.0, 3.0, 5.0},
 				default_value = DKOPTREADER_CONFIG_DEFECT_SIZE,
 				event = "DefectSizeUpdate",
 			},
diff --git a/frontend/ui/device.lua b/frontend/ui/device.lua
index 4a43e89a4..ac4460d44 100644
--- a/frontend/ui/device.lua
+++ b/frontend/ui/device.lua
@@ -99,7 +99,8 @@ function Device:isKobo()
 end
 
 function Device:hasNoKeyboard()
-	return self:isTouchDevice() or (self:getModel() == "Kindle4")
+	local model = self:getModel()
+	return (model == "KindlePaperWhite") or (model == "KindleTouch") or self:isKobo()
 end
 
 function Device:hasKeyboard()
diff --git a/frontend/ui/reader/readerview.lua b/frontend/ui/reader/readerview.lua
index c97038363..e7564f353 100644
--- a/frontend/ui/reader/readerview.lua
+++ b/frontend/ui/reader/readerview.lua
@@ -434,7 +434,6 @@ function ReaderView:onSetScreenMode(new_mode, rotation)
 
 	if new_mode == "landscape" and self.document.info.has_pages then
 		self.ui:handleEvent(Event:new("SetZoomMode", "contentwidth"))
-		self.ui:handleEvent(Event:new("InitScrollPageStates"))
 	end
 	return true
 end
@@ -482,6 +481,7 @@ function ReaderView:onReadSettings(config)
 	self.render_mode = config:readSetting("render_mode") or 0
 	local screen_mode = config:readSetting("screen_mode")
 	if screen_mode then
+		Screen:setScreenMode(screen_mode)
 	    table.insert(self.ui.postInitCallback, function()
 	        self:onSetScreenMode(screen_mode, config:readSetting("rotation_mode"))
 	    end)
diff --git a/frontend/ui/widget/config.lua b/frontend/ui/widget/config.lua
index 2bcb3bf97..001439a7e 100644
--- a/frontend/ui/widget/config.lua
+++ b/frontend/ui/widget/config.lua
@@ -323,6 +323,7 @@ function ConfigOption:init()
 
 			if self.options[c].toggle then
 				local switch = ToggleSwitch:new{
+					width = scaleByDPI(self.options[c].width or 216),
 					name = self.options[c].name,
 					toggle = self.options[c].toggle,
 					alternate = self.options[c].alternate,
diff --git a/frontend/ui/widget/filechooser.lua b/frontend/ui/widget/filechooser.lua
index 86cd45afe..cb042f4d3 100644
--- a/frontend/ui/widget/filechooser.lua
+++ b/frontend/ui/widget/filechooser.lua
@@ -6,7 +6,7 @@ FileChooser = Menu:extend{
 	no_title = true,
 	path = lfs.currentdir(),
 	parent = nil,
-	show_hidden = false,
+	show_hidden = DSHOWHIDDENFILES,
 	filter = function(filename) return true end,
 }
 
diff --git a/frontend/ui/widget/menu.lua b/frontend/ui/widget/menu.lua
index 2d71a99b4..dcc200fb6 100644
--- a/frontend/ui/widget/menu.lua
+++ b/frontend/ui/widget/menu.lua
@@ -32,6 +32,7 @@ function ItemShortCutIcon:init()
 	end
 
 	--@TODO calculate font size by icon size  01.05 2012 (houqp)
+	local sc_face = nil
 	if self.key:len() > 1 then
 		sc_face = Font:getFace("ffont", 14)
 	else
@@ -49,6 +50,7 @@ function ItemShortCutIcon:init()
 			TextWidget:new{
 				text = self.key,
 				face = sc_face,
+				bgcolor = background/15,
 			},
 		},
 	}
@@ -123,7 +125,8 @@ function MenuItem:init()
 				doc = "Select Menu Item",
 			},
 		}
-	else
+	end
+	if Device:hasKeyboard() then
 		self.active_key_events = {
 			Select = { {"Press"}, doc = "chose selected item" },
 		}
@@ -261,6 +264,10 @@ function Menu:_recalculateDimen()
 	}
 	self.perpage = math.floor((self.dimen.h - self.dimen.x) / self.item_dimen.h) - 2
 	self.page_num = math.ceil(#self.item_table / self.perpage)
+	-- update page info layout, fixed #281
+	if self.page_info then
+		self.page_info:resetLayout()
+	end
 end
 
 function Menu:init()
@@ -374,7 +381,8 @@ function Menu:init()
 				range = self.dimen,
 			}
 		}
-	else
+	end
+	if Device:hasKeyboard() then
 		-- set up keyboard events
 		self.key_events.Close = { {"Back"}, doc = _("close menu") }
 		self.key_events.NextPage = {
diff --git a/frontend/ui/widget/toggleswitch.lua b/frontend/ui/widget/toggleswitch.lua
index 620ad5059..47a31819a 100644
--- a/frontend/ui/widget/toggleswitch.lua
+++ b/frontend/ui/widget/toggleswitch.lua
@@ -11,6 +11,8 @@ end
 ToggleSwitch = InputContainer:new{
 	width = scaleByDPI(216),
 	height = scaleByDPI(30),
+	bgcolor = 0, -- unfoused item color
+	fgcolor = 7, -- focused item color
 }
 
 function ToggleSwitch:init()
@@ -65,13 +67,13 @@ function ToggleSwitch:update()
 	local pos = self.position
 	for i=1,#self.toggle_content do
 		if pos == i then
-			self.toggle_content[i].color = 7
-			self.toggle_content[i].background = 7
-			self.toggle_content[i][1][1].bgcolor = 0.5
+			self.toggle_content[i].color = self.fgcolor
+			self.toggle_content[i].background = self.fgcolor
+			self.toggle_content[i][1][1].bgcolor = self.fgcolor/15
 			self.toggle_content[i][1][1].fgcolor = 0.0
 		else
-			self.toggle_content[i].color = 0
-			self.toggle_content[i].background = 0
+			self.toggle_content[i].color = self.bgcolor
+			self.toggle_content[i].background = self.bgcolor
 			self.toggle_content[i][1][1].bgcolor = 0.0
 			self.toggle_content[i][1][1].fgcolor = 1.0
 		end