diff --git a/startup b/startup
index a6631fb..47678d3 100644
--- a/startup
+++ b/startup
@@ -6,7 +6,7 @@ local term     = _G.term
 local bootOptions = {
 	{ prompt = os.version() },
 	{ prompt = 'Opus'         , args = { '/sys/boot/opus.boot' } },
-	{ prompt = 'Opus Shell'   , args = { '/sys/boot/opus.boot', 'sys/apps/shell' } },
+	{ prompt = 'Opus Shell'   , args = { '/sys/boot/opus.boot', 'sys/apps/shell.lua' } },
 	{ prompt = 'Opus Kiosk'   , args = { '/sys/boot/kiosk.boot' } },
 }
 local bootOption = 2
diff --git a/sys/apis/terminal.lua b/sys/apis/terminal.lua
index bfac681..904f36e 100644
--- a/sys/apis/terminal.lua
+++ b/sys/apis/terminal.lua
@@ -25,8 +25,8 @@ function Terminal.window(parent, sx, sy, w, h, isVisible)
 		width   = w,
 		height  = h,
 		isColor = parent.isColor(),
+		offy    = 0,
 	})
-	canvas.offy = 0
 
 	win.canvas = canvas
 
@@ -164,7 +164,7 @@ function Terminal.window(parent, sx, sy, w, h, isVisible)
 	function win.redraw()
 		if isVisible then
 			canvas:dirty()
-			canvas:render(parent)
+			update()
 		end
 	end
 
diff --git a/sys/apis/ui/canvas.lua b/sys/apis/ui/canvas.lua
index 55f2977..d980845 100644
--- a/sys/apis/ui/canvas.lua
+++ b/sys/apis/ui/canvas.lua
@@ -198,10 +198,12 @@ function Canvas:blit(x, y, text, bg, fg)
 end
 
 function Canvas:writeLine(y, text, fg, bg)
-	self.lines[y].dirty = true
-	self.lines[y].text = text
-	self.lines[y].fg = fg
-	self.lines[y].bg = bg
+	if y > 0 and y <= #self.lines then
+		self.lines[y].dirty = true
+		self.lines[y].text = text
+		self.lines[y].fg = fg
+		self.lines[y].bg = bg
+	end
 end
 
 function Canvas:clearLine(y, bg, fg)
diff --git a/sys/apis/ui/components/Checkbox.lua b/sys/apis/ui/components/Checkbox.lua
index 9f2c174..a780c42 100644
--- a/sys/apis/ui/components/Checkbox.lua
+++ b/sys/apis/ui/components/Checkbox.lua
@@ -15,20 +15,12 @@ UI.Checkbox.defaults = {
 	backgroundColor = colors.black,
 	backgroundFocusColor = colors.lightGray,
 	height = 1,
+	width = 3,
 	accelerators = {
 		space = 'checkbox_toggle',
 		mouse_click = 'checkbox_toggle',
 	}
 }
-function UI.Checkbox:setParent()
-	if not self.width and not self.ex then
-		self.width = (self.label and #self.label or 0) + 3
-	else
-		self.width = 3
-	end
-	UI.Window.setParent(self)
-end
-
 function UI.Checkbox:draw()
 	local bg = self.backgroundColor
 	if self.focused then
diff --git a/sys/apps/Files.lua b/sys/apps/Files.lua
index 1053e79..2e065ba 100644
--- a/sys/apps/Files.lua
+++ b/sys/apps/Files.lua
@@ -347,7 +347,7 @@ function Browser:eventHandler(event)
     self:run('cedit', file.name)
 
   elseif event.type == 'shell' then
-    self:run('sys/apps/shell')
+    self:run('sys/apps/shell.lua')
 
   elseif event.type == 'refresh' then
     self:updateDirectory(self.dir)
diff --git a/sys/apps/Lua.lua b/sys/apps/Lua.lua
index dd50147..a1a3385 100644
--- a/sys/apps/Lua.lua
+++ b/sys/apps/Lua.lua
@@ -1,8 +1,5 @@
-if not _G.requireInjector then
-	local BASE ='https://raw.githubusercontent.com/kepler155c/opus/develop-1.8/sys/apis'
-	_ENV.LUA_PATH=BASE .. '/?.lua'
-	load(_G.http.get(BASE .. '/injector.lua').readAll())()(_ENV)
-end
+-- Lua may be called from outside of shell - inject a require
+_G.requireInjector(_ENV)
 
 local History    = require('history')
 local UI         = require('ui')
diff --git a/sys/apps/Overview.lua b/sys/apps/Overview.lua
index 7deedda..952137d 100644
--- a/sys/apps/Overview.lua
+++ b/sys/apps/Overview.lua
@@ -424,7 +424,7 @@ function page:eventHandler(event)
 		shell.switchTab(shell.openTab(event.button.app.run))
 
 	elseif event.type == 'shell' then
-		shell.switchTab(shell.openTab('sys/apps/shell'))
+		shell.switchTab(shell.openTab('sys/apps/shell.lua'))
 
 	elseif event.type == 'lua' then
 		shell.switchTab(shell.openTab('sys/apps/Lua.lua'))
diff --git a/sys/apps/PackageManager.lua b/sys/apps/PackageManager.lua
index 73cd78b..cdd1641 100644
--- a/sys/apps/PackageManager.lua
+++ b/sys/apps/PackageManager.lua
@@ -36,7 +36,6 @@ local page = UI.Page {
 	description = UI.TextArea {
 		x = 16, y = 3, ey = -5,
 		marginRight = 0, marginLeft = 0,
-		--backgroundColor = colors.white,
 	},
 	load = UI.Button {
 		x = 22, y = -3,
@@ -45,10 +44,8 @@ local page = UI.Page {
 		help = 'Download the latest package list',
 	},
 	action = UI.SlideOut {
-		backgroundColor = colors.brown,
-		y = 3,
+		backgroundColor = colors.cyan,
 		titleBar = UI.TitleBar {
-			backgroundColor = colors.brown,
 			event = 'hide-action',
 		},
 		button = UI.Button {
diff --git a/sys/apps/shell b/sys/apps/shell.lua
similarity index 98%
rename from sys/apps/shell
rename to sys/apps/shell.lua
index d9da2e2..68fc0b3 100644
--- a/sys/apps/shell
+++ b/sys/apps/shell.lua
@@ -314,9 +314,9 @@ function shell.newTab(tabInfo, ...)
 		tabInfo.args = args
 		tabInfo.title = fs.getName(path):match('([^%.]+)')
 
-		if path ~= 'sys/apps/shell' then
+		if path ~= 'sys/apps/shell.lua' then
 			table.insert(tabInfo.args, 1, tabInfo.path)
-			tabInfo.path = 'sys/apps/shell'
+			tabInfo.path = 'sys/apps/shell.lua'
 		end
 		return _ENV.multishell.openTab(tabInfo)
 	end
@@ -329,10 +329,10 @@ function shell.openTab( ... )
 	local sCommand = tWords[1]
 	if sCommand then
 		local sPath = shell.resolveProgram(sCommand)
-		if sPath == "sys/apps/shell" then
+		if sPath == "sys/apps/shell.lua" then
 			return _ENV.multishell.launch(Util.shallowCopy(sandboxEnv), sPath, table.unpack(tWords, 2))
 		else
-			return _ENV.multishell.launch(Util.shallowCopy(sandboxEnv), "sys/apps/shell", sCommand, table.unpack(tWords, 2))
+			return _ENV.multishell.launch(Util.shallowCopy(sandboxEnv), "sys/apps/shell.lua", sCommand, table.unpack(tWords, 2))
 		end
 	end
 end
diff --git a/sys/autorun/upgraded.lua b/sys/autorun/upgraded.lua
new file mode 100644
index 0000000..4992f7d
--- /dev/null
+++ b/sys/autorun/upgraded.lua
@@ -0,0 +1,3 @@
+if fs.exists('sys/apps/shell') and fs.exists('sys/apps/shell.lua') then
+  fs.delete('sys/apps/shell')
+end
diff --git a/sys/boot/opus.boot b/sys/boot/opus.boot
index 2f64980..69b90d3 100644
--- a/sys/boot/opus.boot
+++ b/sys/boot/opus.boot
@@ -64,7 +64,7 @@ else
 	fs.mount('', 'gitfs', GIT_REPO)
 end
 
-local s, m = pcall(run, 'sys/apps/shell', 'sys/kernel.lua', ...)
+local s, m = pcall(run, 'sys/apps/shell.lua', 'sys/kernel.lua', ...)
 
 if not s then
 	print('\nError loading Opus OS\n')
diff --git a/sys/kernel.lua b/sys/kernel.lua
index 407f217..bad6b82 100644
--- a/sys/kernel.lua
+++ b/sys/kernel.lua
@@ -278,7 +278,7 @@ local function init(...)
 		kernel.hook('kernel_ready', function()
 			local s, m = kernel.run({
 				title = args[1],
-				path = 'sys/apps/shell',
+				path = 'sys/apps/shell.lua',
 				args = args,
 				haltOnExit = true,
 				haltOnError = true,
diff --git a/sys/network/telnet.lua b/sys/network/telnet.lua
index c0d5f07..e840a6e 100644
--- a/sys/network/telnet.lua
+++ b/sys/network/telnet.lua
@@ -46,7 +46,7 @@ local function telnetHost(socket)
 		title = 'Telnet client',
 		hidden = true,
 		co = coroutine.create(function()
-			Util.run(_ENV, 'sys/apps/shell', table.unpack(termInfo.program))
+			Util.run(_ENV, 'sys/apps/shell.lua', table.unpack(termInfo.program))
 			if socket.queue then
 				socket:write(socket.queue)
 			end