diff --git a/frontend/ui/widget/menu.lua b/frontend/ui/widget/menu.lua
index 6b64e8249..89aea9673 100644
--- a/frontend/ui/widget/menu.lua
+++ b/frontend/ui/widget/menu.lua
@@ -88,7 +88,7 @@ local MenuCloseButton = InputContainer:new{
     overlap_align = "right",
     padding_right = 0,
     menu = nil,
-    dimen = Geom:new{},
+    dimen = nil,
 }
 
 function MenuCloseButton:init()
@@ -544,8 +544,8 @@ local Menu = FocusManager:new{
     -- height will be calculated according to item number if not given
     height = nil,
     header_padding = Size.padding.large,
-    dimen = Geom:new{},
-    item_table = {},
+    dimen = nil,
+    item_table = nil, -- NOT mandatory (will be empty)
     item_shortcuts = {
         "Q", "W", "E", "R", "T", "Y", "U", "I", "O", "P",
         "A", "S", "D", "F", "G", "H", "J", "K", "L", "Del",
@@ -605,9 +605,9 @@ end
 
 function Menu:init()
     self.show_parent = self.show_parent or self
+    self.item_table = self.item_table or {}
     self.item_table_stack = {}
-    self.dimen.w = self.width
-    self.dimen.h = self.height or Screen:getHeight()
+    self.dimen = Geom:new{ w = self.width, h = self.height or Screen:getHeight() }
     if self.dimen.h > Screen:getHeight() or self.dimen.h == nil then
         self.dimen.h = Screen:getHeight()
     end
diff --git a/frontend/ui/widget/sortwidget.lua b/frontend/ui/widget/sortwidget.lua
index 30288e524..f822ac7a4 100644
--- a/frontend/ui/widget/sortwidget.lua
+++ b/frontend/ui/widget/sortwidget.lua
@@ -149,7 +149,7 @@ local SortWidget = InputContainer:new{
     -- index for the first item to show
     show_page = 1,
     -- table of items to sort
-    item_table = {},
+    item_table = nil, -- mandatory
     callback = nil,
 }
 
diff --git a/frontend/ui/widget/touchmenu.lua b/frontend/ui/widget/touchmenu.lua
index 541d67ff5..01186215d 100644
--- a/frontend/ui/widget/touchmenu.lua
+++ b/frontend/ui/widget/touchmenu.lua
@@ -417,7 +417,7 @@ end
 TouchMenu widget for hierarchical menus
 --]]
 local TouchMenu = FocusManager:new{
-    tab_item_table = {},
+    tab_item_table = nil, -- mandatory
     -- for returning in multi-level menus
     item_table_stack = nil,
     item_table = nil,
diff --git a/plugins/calibre.koplugin/search.lua b/plugins/calibre.koplugin/search.lua
index d9b6e24f3..bd0c9c7cf 100644
--- a/plugins/calibre.koplugin/search.lua
+++ b/plugins/calibre.koplugin/search.lua
@@ -331,7 +331,7 @@ function CalibreSearch:find(option)
         local result = self:bookCatalog(books)
         self:showresults(result)
     else
-        self:browse(option,1)
+        self:browse(option, 1)
     end
     logger.info(string.format("search done in %.3f milliseconds (%s, %s, %s, %s, %s)",
         (TimeVal:now() - start):tomsecs(),