File manager: fix classic mode item font size (#11626)

Closes #11625.

frontend/apps/filemanager/filemanagermenu.lua

@@ -172,7 +172,8 @@ function FileManagerMenu:setUpdateItemTable()
                 sub_item_table = {
                     {
                         text_func = function()
-                            return T(_("Items per page: %1"), G_reader_settings:readSetting("items_per_page"))
+                            return T(_("Items per page: %1"),
+                                G_reader_settings:readSetting("items_per_page") or FileChooser.items_per_page_default)
                         end,
                         help_text = _([[This sets the number of items per page in:
 - File browser, history and favorites in 'classic' display mode
@@ -180,8 +181,8 @@ function FileManagerMenu:setUpdateItemTable()
 - File and folder selection
 - Calibre and OPDS browsers/search results]]),
                         callback = function(touchmenu_instance)
-                            local current_value = G_reader_settings:readSetting("items_per_page")
                             local default_value = FileChooser.items_per_page_default
+                            local current_value = G_reader_settings:readSetting("items_per_page") or default_value
                             local widget = SpinWidget:new{
                                 title_text =  _("Items per page"),
                                 value = current_value,
@@ -204,7 +205,8 @@ function FileManagerMenu:setUpdateItemTable()
                         end,
                         callback = function(touchmenu_instance)
                             local current_value = FileChooser.font_size
-                            local default_value = FileChooser.getItemFontSize(G_reader_settings:readSetting("items_per_page"))
+                            local default_value = FileChooser.getItemFontSize(G_reader_settings:readSetting("items_per_page")
+                                or FileChooser.items_per_page_default)
                             local widget = SpinWidget:new{
                                 title_text =  _("Item font size"),
                                 value = current_value,