diff --git a/frontend/apps/filemanager/filemanagermenu.lua b/frontend/apps/filemanager/filemanagermenu.lua
index 430b87d9d..59ec2fe5a 100644
--- a/frontend/apps/filemanager/filemanagermenu.lua
+++ b/frontend/apps/filemanager/filemanagermenu.lua
@@ -1,18 +1,18 @@
 local CenterContainer = require("ui/widget/container/centercontainer")
-local InputContainer = require("ui/widget/container/inputcontainer")
+local CloudStorage = require("apps/cloudstorage/cloudstorage")
 local ConfirmBox = require("ui/widget/confirmbox")
-local UIManager = require("ui/uimanager")
+local Device = require("device")
+local FileSearcher = require("apps/filemanager/filemanagerfilesearcher")
+local Geom = require("ui/geometry")
 local GestureRange = require("ui/gesturerange")
+local InputContainer = require("ui/widget/container/inputcontainer")
 local InputDialog = require("ui/widget/inputdialog")
-local Geom = require("ui/geometry")
-local Device = require("device")
 local Screensaver = require("ui/screensaver")
-local Screen = Device.screen
-local _ = require("gettext")
-local FileSearcher = require("apps/filemanager/filemanagerfilesearcher")
 local Search = require("apps/filemanager/filemanagersearch")
 local SetDefaults = require("apps/filemanager/filemanagersetdefaults")
-local CloudStorage = require("apps/cloudstorage/cloudstorage")
+local UIManager = require("ui/uimanager")
+local _ = require("gettext")
+local Screen = Device.screen
 
 local FileManagerMenu = InputContainer:extend{
     tab_item_table = nil,
diff --git a/frontend/apps/reader/modules/readermenu.lua b/frontend/apps/reader/modules/readermenu.lua
index 5d53e38ca..5f88e10ae 100644
--- a/frontend/apps/reader/modules/readermenu.lua
+++ b/frontend/apps/reader/modules/readermenu.lua
@@ -1,11 +1,11 @@
-local InputContainer = require("ui/widget/container/inputcontainer")
 local CenterContainer = require("ui/widget/container/centercontainer")
-local UIManager = require("ui/uimanager")
 local Device = require("device")
-local Screensaver = require("ui/screensaver")
 local Event = require("ui/event")
-local Screen = require("device").screen
+local InputContainer = require("ui/widget/container/inputcontainer")
+local Screensaver = require("ui/screensaver")
+local UIManager = require("ui/uimanager")
 local _ = require("gettext")
+local Screen = require("device").screen
 
 local ReaderMenu = InputContainer:new{
     tab_item_table = nil,
diff --git a/frontend/luasettings.lua b/frontend/luasettings.lua
index a08707329..4747ad22e 100644
--- a/frontend/luasettings.lua
+++ b/frontend/luasettings.lua
@@ -16,6 +16,16 @@ function LuaSettings:open(file_path)
     return setmetatable(new, {__index = LuaSettings})
 end
 
+-- TODO: DocSettings can return a LuaSettings to use following awesome features.
+function LuaSettings:wrap(data)
+    local new = {data = type(data) == "table" and data or {}}
+    return setmetatable(new, {__index = LuaSettings})
+end
+
+function LuaSettings:child(key)
+    return LuaSettings:wrap(self:readSetting(key))
+end
+
 function LuaSettings:readSetting(key)
     return self.data[key]
 end
@@ -40,10 +50,18 @@ function LuaSettings:isTrue(key)
     return string.lower(tostring(self:readSetting(key))) == "true"
 end
 
+function LuaSettings:isFalse(key)
+    return string.lower(tostring(self:readSetting(key))) == "false"
+end
+
 function LuaSettings:nilOrTrue(key)
     return self:hasNot(key) or self:isTrue(key)
 end
 
+function LuaSettings:nilOrFalse(key)
+    return self:hasNot(key) or self:isFalse(key)
+end
+
 function LuaSettings:flipNilOrTrue(key)
     if self:nilOrTrue(key) then
         self:saveSetting(key, false)
@@ -52,6 +70,14 @@ function LuaSettings:flipNilOrTrue(key)
     end
 end
 
+function LuaSettings:flipNilOrFalse(key)
+    if self:nilOrFalse(key) then
+        self:saveSetting(key, true)
+    else
+        self:delSetting(key)
+    end
+end
+
 function LuaSettings:flipTrue(key)
     if self:isTrue(key) then
         self:delSetting(key)
@@ -60,11 +86,20 @@ function LuaSettings:flipTrue(key)
     end
 end
 
+function LuaSettings:flipFalse(key)
+    if self:isFalse(key) then
+        self:delSetting(key)
+    else
+        self:saveSetting(key, true)
+    end
+end
+
 function LuaSettings:reset(table)
     self.data = table
 end
 
 function LuaSettings:flush()
+    if not self.file then return end
     local f_out = io.open(self.file, "w")
     if f_out ~= nil then
         os.setlocale('C', 'numeric')
diff --git a/spec/unit/luasettings_spec.lua b/spec/unit/luasettings_spec.lua
index b020dcb40..9f4069c5e 100644
--- a/spec/unit/luasettings_spec.lua
+++ b/spec/unit/luasettings_spec.lua
@@ -39,4 +39,28 @@ describe("luasettings module", function()
         assert.False(Settings:isTrue("abc"))
         assert.True(Settings:nilOrTrue("abc"))
     end)
+
+    it("should create child settings", function()
+        Settings:saveSetting("key", {
+            a = "b",
+            c = "true",
+            d = false,
+        })
+
+        local child = Settings:child("key")
+
+        assert.is_not_nil(child)
+        assert.True(child:has("a"))
+        assert.are.equal(child:readSetting("a"), "b")
+        assert.True(child:has("c"))
+        assert.True(child:isTrue("c"))
+        assert.True(child:has("d"))
+        assert.True(child:isFalse("d"))
+        assert.False(child:isTrue("e"))
+        child:flipTrue("e")
+        child:close()
+
+        child = Settings:child("key")
+        assert.True(child:isTrue("e"))
+    end)
 end)