diff --git a/lua/harpoon/dev.lua b/lua/harpoon/dev.lua
index e428250..03d622a 100644
--- a/lua/harpoon/dev.lua
+++ b/lua/harpoon/dev.lua
@@ -19,7 +19,7 @@ local function set_log_level()
         end
     end
 
-    return "warn" -- default, if user hasn't set
+    return "warn" -- default, if user hasn't set to one from log_levels
 end
 
 M.log = require("plenary.log").new({
diff --git a/lua/harpoon/init.lua b/lua/harpoon/init.lua
index cef3d04..359fdca 100644
--- a/lua/harpoon/init.lua
+++ b/lua/harpoon/init.lua
@@ -127,13 +127,14 @@ M.setup = function(config)
     end
 
     local ok, u_config = pcall(read_config, user_config)
-    local ok2, c_config = pcall(read_config, cache_config)
 
     if not ok then
         log.debug("setup(): No user config present at", user_config)
         u_config = {}
     end
 
+    local ok2, c_config = pcall(read_config, cache_config)
+
     if not ok2 then
         log.debug("setup(): No cache config present at", cache_config)
         c_config = {}
@@ -156,22 +157,22 @@ M.setup = function(config)
 end
 
 M.get_global_settings = function()
-    log.trace("get_global_settings()")
+    log.debug("get_global_settings()")
     return HarpoonConfig.global_settings
 end
 
 M.get_term_config = function()
-    log.trace("get_term_config()")
+    log.debug("get_term_config()")
     return ensure_correct_config(HarpoonConfig).projects[vim.loop.cwd()].term
 end
 
 M.get_mark_config = function()
-    -- log.trace("get_mark_config()")
+    log.debug("get_mark_config()")
     return ensure_correct_config(HarpoonConfig).projects[vim.loop.cwd()].mark
 end
 
 M.get_menu_config = function()
-    log.trace("get_menu_config()")
+    log.debug("get_menu_config()")
     return HarpoonConfig.menu or {}
 end
 
diff --git a/lua/harpoon/mark.lua b/lua/harpoon/mark.lua
index 225911f..39fb9c6 100644
--- a/lua/harpoon/mark.lua
+++ b/lua/harpoon/mark.lua
@@ -19,7 +19,8 @@ local function emit_changed()
         return
     end
 
-    for _, cb in pairs(callbacks) do
+    for idx, cb in pairs(callbacks["changed"]) do
+        log.debug(string.format("emit_changed(): Running callback #%d for 'changed'", idx))
         cb()
     end
 end
@@ -36,6 +37,7 @@ local function filter_empty_string(list)
 end
 
 local function get_first_empty_slot()
+    log.debug("_get_first_empty_slot()")
     for idx = 1, M.get_length() do
         local filename = M.get_marked_file_name(idx)
         if filename == "" then
@@ -47,6 +49,7 @@ local function get_first_empty_slot()
 end
 
 local function get_buf_name(id)
+    log.debug("get_buf_name():", id)
     if id == nil then
         return utils.normalize_path(vim.fn.bufname(vim.fn.bufnr()))
     elseif type(id) == "string" then
@@ -72,25 +75,29 @@ local function create_mark(filename)
 end
 
 local function mark_exists(buf_name)
+    log.debug("_mark_exists()")
     for idx = 1, M.get_length() do
         if M.get_marked_file_name(idx) == buf_name then
+            log.trace("_mark_exists(): Mark exists", buf_name)
             return true
         end
     end
 
+    log.trace("_mark_exists(): Mark doesn't exist", buf_name)
     return false
 end
 
 local function validate_buf_name(buf_name)
     if buf_name == "" or buf_name == nil then
-        log.error("Couldn't find a valid file name to mark, sorry.")
+        log.error("validate_buf_name(): Not a valid name for a mark,", buf_name)
         return
     end
 end
 
 M.get_index_of = function(item)
+    log.debug("get_index_of():", item)
     if item == nil then
-        log.error("You have provided a nil value to Harpoon, please provide a string rep of the file or the file idx.")
+        log.error("get_index_of(): You have provided a nil value to Harpoon, please provide a string rep of the file or the file idx.")
         return
     end
 
@@ -105,6 +112,7 @@ M.get_index_of = function(item)
         return nil
     end
 
+    -- TODO move this to a "harpoon_" prefix?
     if vim.g.manage_a_mark_zero_index then
         item = item + 1
     end
@@ -113,10 +121,12 @@ M.get_index_of = function(item)
         return item
     end
 
+    log.debug("get_index_of(): No item found,", item)
     return nil
 end
 
 M.status = function()
+    log.debug("status()")
     local idx = M.get_index_of(get_buf_name())
 
     if M.valid_index(idx) then
@@ -126,6 +136,7 @@ M.status = function()
 end
 
 M.valid_index = function(idx)
+    log.debug("valid_index():", idx)
     if idx == nil then
         return false
     end
@@ -136,6 +147,7 @@ end
 
 M.add_file = function(file_name_or_buf_id)
     local buf_name = get_buf_name(file_name_or_buf_id)
+    log.debug("add_file():", buf_name)
 
     if M.valid_index(M.get_index_of(buf_name)) then
         -- we don't alter file layout.
@@ -150,8 +162,9 @@ M.add_file = function(file_name_or_buf_id)
     emit_changed()
 end
 
--- dont_emit_on_changed should only be used internally
+-- _emit_on_changed == false should only be used internally
 M.remove_empty_tail = function(_emit_on_changed)
+    log.debug("remove_empty_tail()")
     _emit_on_changed = _emit_on_changed == nil or _emit_on_changed
     local config = harpoon.get_mark_config()
     local found = false
@@ -174,18 +187,22 @@ M.remove_empty_tail = function(_emit_on_changed)
 end
 
 M.store_offset = function()
+    log.debug("store_offset()")
     local ok, res = pcall(function()
         local buf_name = get_buf_name()
         local idx = M.get_index_of(buf_name)
+
         if not M.valid_index(idx) then
             return
         end
 
-        harpoon.get_mark_config().marks[idx].row = vim.fn.line(".")
+        local line = vim.fn.line(".")
+        harpoon.get_mark_config().marks[idx].row = line
+        log.debug("store_offset(): Stored line:", line)
     end)
 
     if not ok then
-        log.warn("store_offset(): pcall failed:", res)
+        log.warn("store_offset(): Could not store offset:", res)
     end
 
     emit_changed()
@@ -214,6 +231,7 @@ end
 
 --- ENTERPRISE PROGRAMMING
 M.get_marked_file = function(idxOrName)
+    log.debug("get_marked_file():", idxOrName)
     if type(idxOrName) == "string" then
         idxOrName = M.get_index_of(idxOrName)
     end
@@ -222,10 +240,12 @@ end
 
 M.get_marked_file_name = function(idx)
     local mark = harpoon.get_mark_config().marks[idx]
+    log.debug("get_marked_file_name():", mark and mark.filename)
     return mark and mark.filename
 end
 
 M.get_length = function()
+    log.debug("get_length()")
     return table.maxn(harpoon.get_mark_config().marks)
 end
 
@@ -270,6 +290,9 @@ M.to_quickfix_list = function()
 end
 
 M.set_mark_list = function(new_list)
+    log.debug("set_mark_list()")
+    log.trace("set_mark_list(): new_list", new_list)
+
     local config = harpoon.get_mark_config()
 
     for k, v in pairs(new_list) do
@@ -306,16 +329,19 @@ M.toggle_file = function(file_name_or_buf_id)
 end
 
 M.get_current_index = function()
+    log.debug("get_current_index()")
     return M.get_index_of(vim.fn.bufname(vim.fn.bufnr()))
 end
 
 M.on = function(event, cb)
+    log.debug("on():", event)
     if not callbacks[event] then
         log.debug("on(): no callbacks yet for", event)
         callbacks[event] = {}
     end
 
     table.insert(callbacks[event], cb)
+    log.trace(callbacks)
 end
 
 return M
diff --git a/lua/harpoon/ui.lua b/lua/harpoon/ui.lua
index a94d739..92d3936 100644
--- a/lua/harpoon/ui.lua
+++ b/lua/harpoon/ui.lua
@@ -9,15 +9,16 @@ Harpoon_win_id = nil
 Harpoon_bufh = nil
 
 local function create_window()
+    log.debug("_create_window()")
     local config = harpoon.get_menu_config()
     local width = config.width or 60
     local height = config.height or 10
-    local borderchars = config.borderchars or { '─', '│', '─', '│', '╭', '╮', '╯', '╰' }
+    local borderchars = config.borderchars or { "─", "│", "─", "│", "╭", "╮", "╯", "╰" }
     local bufnr = vim.api.nvim_create_buf(false, false)
 
     local Harpoon_win_id, win = popup.create(bufnr, {
-        title = 'Harpoon',
-        highlight = 'HarpoonWindow',
+        title = "Harpoon",
+        highlight = "HarpoonWindow",
         line = math.floor(((vim.o.lines - height) / 2) - 1),
         col = math.floor((vim.o.columns - width) / 2),
         minwidth = width,
@@ -25,7 +26,7 @@ local function create_window()
         borderchars = borderchars,
     })
 
-    vim.api.nvim_win_set_option(win.border.win_id, 'winhl', 'Normal:HarpoonBorder')
+    vim.api.nvim_win_set_option(win.border.win_id, "winhl", "Normal:HarpoonBorder")
 
     return {
         bufnr = bufnr,
@@ -38,7 +39,7 @@ local function get_menu_items()
     local indices = {}
 
     for idx = 1, #lines do
-        local space_location = string.find(lines[idx], ' ')
+        local space_location = string.find(lines[idx], " ")
 
         if space_location ~= nil then
             table.insert(indices, string.sub(lines[idx], space_location + 1))
@@ -48,16 +49,13 @@ local function get_menu_items()
     return indices
 end
 
-local save_changes = function()
-    Marked.set_mark_list(get_menu_items())
-end
-
 M.toggle_quick_menu = function()
+    log.debug("toggle_quick_menu()")
     if Harpoon_win_id ~= nil and vim.api.nvim_win_is_valid(Harpoon_win_id) then
         local global_config = harpoon.get_global_settings()
 
         if global_config.save_on_toggle then
-            require('harpoon.ui').on_menu_save()
+            require("harpoon.ui").on_menu_save()
         end
 
         vim.api.nvim_win_close(Harpoon_win_id, true)
@@ -92,10 +90,12 @@ M.toggle_quick_menu = function()
 end
 
 M.on_menu_save = function()
-    save_changes()
+    log.debug("on_menu_save()")
+    Marked.set_mark_list(get_menu_items())
 end
 
 M.nav_file = function(id)
+    log.debug("nav_file(): Navigating to", id)
     local idx = Marked.get_index_of(id)
     if not Marked.valid_index(idx) then
         log.debug("nav_file(): No mark exists for id", id)
@@ -108,20 +108,23 @@ M.nav_file = function(id)
 
     vim.api.nvim_set_current_buf(buf_id)
     if set_row and mark.row then
-        vim.cmd(string.format(":%d", mark.row))
+        local ok, err = pcall(vim.cmd, string.format(":%d", mark.row))
+        if not ok then
+            log.warn("nav_file(): Could not set row to", mark.row, err)
+        end
     end
 end
 
 function M.location_window(options)
     local default_options = {
-        relative = 'editor',
-        style = 'minimal',
+        relative = "editor",
+        style = "minimal",
         width = 30,
         height = 15,
         row = 2,
         col = 2,
     }
-    options = vim.tbl_extend('keep', options, default_options)
+    options = vim.tbl_extend("keep", options, default_options)
 
     local bufnr = options.bufnr or vim.fn.nvim_create_buf(false, true)
     local win_id = vim.fn.nvim_open_win(bufnr, true, options)
@@ -142,15 +145,15 @@ function M.notification(text)
         width = 20,
         height = 2,
         row = 1,
-        col = win_width - 21
+        col = win_width - 21,
     })
 
-    vim.api.nvim_buf_set_lines(info.bufnr, 0, 5, false, {"!!! Notification", text})
+    vim.api.nvim_buf_set_lines(info.bufnr, 0, 5, false, { "!!! Notification", text })
     vim.api.nvim_set_current_win(prev_win)
 
     return {
         bufnr = info.bufnr,
-        win_id = info.win_id
+        win_id = info.win_id,
     }
 end
 
@@ -159,32 +162,34 @@ function M.close_notification(bufnr)
 end
 
 M.nav_next = function()
+    log.debug("nav_next()")
     local current_index = Marked.get_current_index()
     local number_of_items = Marked.get_length()
 
-    if current_index  == nil then
+    if current_index == nil then
         current_index = 1
     else
         current_index = current_index + 1
     end
 
-    if (current_index > number_of_items)  then
+    if (current_index > number_of_items) then
         current_index = 1
     end
     M.nav_file(current_index)
 end
 
 M.nav_prev = function()
+    log.debug("nav_prev()")
     local current_index = Marked.get_current_index()
     local number_of_items = Marked.get_length()
 
-    if current_index  == nil then
+    if current_index == nil then
         current_index = number_of_items
     else
         current_index = current_index - 1
     end
 
-    if (current_index < 1)  then
+    if (current_index < 1) then
         current_index = number_of_items
     end
 
@@ -192,4 +197,3 @@ M.nav_prev = function()
 end
 
 return M
-