diff --git a/sys/apis/class.lua b/sys/apis/class.lua
index ced9020..4b5ed06 100644
--- a/sys/apis/class.lua
+++ b/sys/apis/class.lua
@@ -1,6 +1,8 @@
 -- From http://lua-users.org/wiki/SimpleLuaClasses
 -- (with some modifications)
 
+local uid = 1
+
 -- class.lua
 -- Compatible with Lua 5.1 (not 5.0).
 return function(base)
@@ -19,7 +21,8 @@ return function(base)
   -- expose a constructor which can be called by <classname>(<args>)
   setmetatable(c, {
     __call = function(class_tbl, ...)
-      local obj = {}
+      local obj = { __uid = uid }
+      uid = uid + 1
       setmetatable(obj,c)
       if class_tbl.init then
         class_tbl.init(obj, ...)
diff --git a/sys/apis/injector.lua b/sys/apis/injector.lua
index 7e3f847..12c92ad 100644
--- a/sys/apis/injector.lua
+++ b/sys/apis/injector.lua
@@ -21,16 +21,13 @@ if not http._patched then
     else
       syncLocks[key] = { }
     end
-    local s, m = pcall(fn)
+    fn()
     local co = table.remove(syncLocks[key], 1)
     if co then
       os.queueEvent('sync_lock', co)
     else
       syncLocks[key] = nil
     end
-    if not s then
-      error(m)
-    end
   end
 
   -- todo -- completely replace http.get with function that
diff --git a/sys/apis/ui.lua b/sys/apis/ui.lua
index 650a2fb..b468d0f 100644
--- a/sys/apis/ui.lua
+++ b/sys/apis/ui.lua
@@ -9,6 +9,13 @@ local _sub   = string.sub
 local colors = _G.colors
 local keys   = _G.keys
 
+--[[
+  Using the shorthand window definition, elements are created from
+  the bottom up. Once reaching the top, setParent is called top down.
+
+  On :init(), elements do not know the parent or can calculate sizing.
+]]
+
 local function safeValue(v)
   local t = type(v)
   if t == 'string' or t == 'number' then
@@ -526,7 +533,6 @@ UI.Window.defaults = {
 function UI.Window:init(args)
   local defaults = UI:getDefaults(UI.Window, args)
   UI:setProperties(self, defaults)
-
   if self.parent then
     self:setParent()
   end
@@ -2024,6 +2030,7 @@ UI.MenuBar.defaults = {
   backgroundColor = colors.lightGray,
   textColor = colors.black,
   spacing = 2,
+  lastx = 1,
   showBackButton = false,
   buttonClass = 'MenuItem',
 }
@@ -2031,23 +2038,40 @@ UI.MenuBar.spacer = { spacer = true, text = 'spacer', inactive = true }
 
 function UI.MenuBar:init(args)
   local defaults = UI:getDefaults(UI.MenuBar, args)
-  UI:setProperties(self, defaults)
+  UI.Window.init(self, defaults)
 
   if not self.children then
     self.children = { }
   end
 
-  local x = 1
-  for _,button in pairs(self.buttons) do
+  self:addButtons(self.buttons)
+  if self.showBackButton then
+    table.insert(self.children, UI.MenuItem({
+      x = UI.term.width - 2,
+      width = 3,
+      backgroundColor = self.backgroundColor,
+      textColor = self.textColor,
+      text = '^-',
+      event = 'back',
+    }))
+  end
+end
+
+function UI.MenuBar:addButtons(buttons)
+  if not self.children then
+    self.children = { }
+  end
+
+  for _,button in pairs(buttons) do
     if button.UIElement then
       table.insert(self.children, button)
     else
       local buttonProperties = {
-        x = x,
+        x = self.lastx,
         width = #button.text + self.spacing,
         centered = false,
       }
-      x = x + buttonProperties.width
+      self.lastx = self.lastx + buttonProperties.width
       UI:setProperties(buttonProperties, button)
 
       button = UI[self.buttonClass](buttonProperties)
@@ -2059,21 +2083,10 @@ function UI.MenuBar:init(args)
 
       if button.dropdown then
         button.dropmenu = UI.DropMenu { buttons = button.dropdown }
-        --table.insert(self.children, buttonProperties.dropmenu)
       end
     end
   end
-  if self.showBackButton then
-    table.insert(self.children, UI.MenuItem({
-      x = UI.term.width - 2,
-      width = 3,
-      backgroundColor = self.backgroundColor,
-      textColor = self.textColor,
-      text = '^-',
-      event = 'back',
-    }))
-  end
-  UI.Window.init(self, defaults)
+  self:initChildren()
 end
 
 function UI.MenuBar:getActive(menuItem)
@@ -2238,42 +2251,44 @@ UI.Tabs.defaults = {
 }
 function UI.Tabs:init(args)
   local defaults = UI:getDefaults(UI.Tabs, args)
+  UI.Window.init(self, defaults)
+
+  self:add(self)
+end
+
+function UI.Tabs:add(children)
 
   local buttons = { }
-  for _,child in pairs(defaults) do
+  for _,child in pairs(children) do
     if type(child) == 'table' and child.UIElement then
+      child.y = 2
       table.insert(buttons, {
-        text = child.tabTitle or '', event = 'tab_select',
+        text = child.tabTitle or '',
+        event = 'tab_select',
+        tabUid = child.__uid,
       })
     end
   end
 
-  self.tabBar = UI.TabBar({
-    buttons = buttons,
-  })
+  if not self.tabBar then
+    self.tabBar = UI.TabBar({
+      buttons = buttons,
+    })
+  else
+    self.tabBar:addButtons(buttons)
+  end
 
-  UI.Window.init(self, defaults)
-end
-
-function UI.Tabs:setParent()
-  UI.Window.setParent(self)
-
-  for _,child in pairs(self.children) do
-    if child ~= self.tabBar then
-      child.oy = 2
-      --child.height = self.height - 1
-      child:resize()
-    end
+  if self.parent then
+    return UI.Window.add(self, children)
   end
 end
 
 function UI.Tabs:enable()
   self.enabled = true
-  for _,child in ipairs(self.children) do
-    if child.tabTitle == self.tabBar.buttons[1].text then
-      self:activateTab(child)
-      break
-    end
+
+  local _, menuItem = Util.first(self.tabBar.children, function(a, b) return a.x < b.x end)
+  if menuItem then
+    self:activateTab(Util.find(self.children, '__uid', menuItem.tabUid))
   end
   self.tabBar:enable()
 end
@@ -2292,11 +2307,9 @@ end
 
 function UI.Tabs:eventHandler(event)
   if event.type == 'tab_select' then
-    for _,child in ipairs(self.children) do
-      if child.tabTitle == event.button.text then
-        self:activateTab(child)
-        break
-      end
+    local child = Util.find(self.children, '__uid', event.button.tabUid)
+    if child then
+      self:activateTab(child)
     end
   elseif event.type == 'tab_change' then
     for _,tab in ipairs(self.children) do
diff --git a/sys/apps/System.lua b/sys/apps/System.lua
index 33a48eb..b21826c 100644
--- a/sys/apps/System.lua
+++ b/sys/apps/System.lua
@@ -7,6 +7,7 @@ local Util   = require('util')
 local fs         = _G.fs
 local multishell = _ENV.multishell
 local os         = _G.os
+local settings   = _G.settings
 local shell      = _ENV.shell
 
 multishell.setTitle(multishell.getCurrent(), 'System')
@@ -57,7 +58,6 @@ local systemPage = UI.Page {
       },
       grid = UI.Grid {
         y = 5,
-        autospace = true,
         sortColumn = 'alias',
         columns = {
           { heading = 'Alias',   key = 'alias' },
@@ -108,6 +108,43 @@ local systemPage = UI.Page {
   },
 }
 
+if settings then
+  local values = { }
+  for _,v in pairs(settings.getNames()) do
+    table.insert(values, {
+      name = v,
+      value = not not settings.get(v),
+    })
+  end
+
+  systemPage.tabs:add({
+    systemTab = UI.Window {
+      tabTitle = 'Settings',
+      grid = UI.Grid {
+        y = 1,
+        values = values,
+        --autospace = true,
+        sortColumn = 'name',
+        columns = {
+          { heading = 'Setting',   key = 'name' },
+          { heading = 'Value', key = 'value'  },
+        },
+        accelerators = {
+        },
+      },
+    }
+  })
+  function systemPage.tabs.systemTab:eventHandler(event)
+    if event.type == 'grid_select' then
+      event.selected.value = not event.selected.value
+      settings.set(event.selected.name, event.selected.value)
+      settings.save('.settings')
+      self.grid:draw()
+      return true
+    end
+  end
+end
+
 function systemPage.tabs.pathTab.grid:draw()
   self.values = { }
   for _,v in ipairs(Util.split(env.path, '(.-):')) do