diff --git a/data/core/commands/core.lua b/data/core/commands/core.lua
index 62be4bc6..16b371f3 100644
--- a/data/core/commands/core.lua
+++ b/data/core/commands/core.lua
@@ -6,6 +6,7 @@ local LogView = require "core.logview"
 
 
 local fullscreen = false
+local restore_title_view = false
 
 local function suggest_directory(text)
   text = common.home_expand(text)
@@ -28,9 +29,12 @@ command.add(nil, {
 
   ["core:toggle-fullscreen"] = function()
     fullscreen = not fullscreen
+    if fullscreen then
+      restore_title_view = core.title_view.visible
+    end
     system.set_window_mode(fullscreen and "fullscreen" or "normal")
-    core.show_title_bar(not fullscreen)
-    core.title_view:configure_hit_test(not fullscreen)
+    core.show_title_bar(not fullscreen and restore_title_view)
+    core.title_view:configure_hit_test(not fullscreen and restore_title_view)
   end,
 
   ["core:reload-module"] = function()
@@ -160,7 +164,10 @@ command.add(nil, {
         core.error("Cannot open folder %q", text)
         return
       end
-      core.confirm_close_docs(core.docs, core.open_folder_project, text)
+      core.confirm_close_docs(core.docs, function(dirpath)
+        core.close_current_project()
+        core.open_folder_project(dirpath)
+      end, text)
     end, suggest_directory)
   end,
 
diff --git a/data/core/doc/highlighter.lua b/data/core/doc/highlighter.lua
index c77e1138..9ba7b634 100644
--- a/data/core/doc/highlighter.lua
+++ b/data/core/doc/highlighter.lua
@@ -1,4 +1,5 @@
 local core = require "core"
+local common = require "core.common"
 local config = require "core.config"
 local tokenizer = require "core.tokenizer"
 local Object = require "core.object"
@@ -40,6 +41,13 @@ end
 
 function Highlighter:reset()
   self.lines = {}
+  self:soft_reset()
+end
+
+function Highlighter:soft_reset()
+  for i=1,#self.lines do
+    self.lines[i] = false
+  end
   self.first_invalid_line = 1
   self.max_wanted_line = 0
 end
@@ -51,16 +59,16 @@ end
 
 function Highlighter:insert_notify(line, n)
   self:invalidate(line)
+  local blanks = { }
   for i = 1, n do
-    table.insert(self.lines, line, false)
+    blanks[i] = false
   end
+  common.splice(self.lines, line, 0, blanks)
 end
 
 function Highlighter:remove_notify(line, n)
   self:invalidate(line)
-  for i = 1, n do
-    table.remove(self.lines, line)
-  end
+  common.splice(self.lines, line, n)
 end
 
 
diff --git a/data/core/doc/init.lua b/data/core/doc/init.lua
index 2e72907a..06cde9f9 100644
--- a/data/core/doc/init.lua
+++ b/data/core/doc/init.lua
@@ -47,7 +47,7 @@ function Doc:reset_syntax()
   local syn = syntax.get(self.filename or "", header)
   if self.syntax ~= syn then
     self.syntax = syn
-    self.highlighter:reset()
+    self.highlighter:soft_reset()
   end
 end
 
@@ -62,12 +62,15 @@ function Doc:load(filename)
   local fp = assert( io.open(filename, "rb") )
   self:reset()
   self.lines = {}
+  local i = 1
   for line in fp:lines() do
     if line:byte(-1) == 13 then
       line = line:sub(1, -2)
       self.crlf = true
     end
     table.insert(self.lines, line .. "\n")
+    self.highlighter.lines[i] = false
+    i = i + 1
   end
   if #self.lines == 0 then
     table.insert(self.lines, "\n")
diff --git a/data/core/init.lua b/data/core/init.lua
index b4d52f54..936de2c6 100644
--- a/data/core/init.lua
+++ b/data/core/init.lua
@@ -65,6 +65,22 @@ function core.set_project_dir(new_dir, change_project_fn)
   return false
 end
 
+function core.close_current_project()
+  -- When using system.unwatch_dir we need to pass the watch_id provided by dmon.
+  -- In reality when unwatching a directory the dmon library shifts the other watch_id
+  -- values so the actual watch_id changes. To workaround this problem we assume the
+  -- first watch_id is always 1 and the watch_id are continguous and we unwatch the
+  -- first watch_id repeateadly up to the number of watch_ids.
+  local watch_id_max = 0
+  for _, project_dir in ipairs(core.project_directories) do
+    if project_dir.watch_id and project_dir.watch_id > watch_id_max then
+      watch_id_max = project_dir.watch_id
+    end
+  end
+  for i = 1, watch_id_max do
+    system.unwatch_dir(1)
+  end
+end
 
 function core.open_folder_project(dir_path_abs)
   if core.set_project_dir(dir_path_abs, core.on_quit_project) then
@@ -200,12 +216,12 @@ local function file_search(files, info)
       inf = curr
     end
   end
-  repeat
+  while inf <= sup and not system.path_compare(filename, type, files[inf].filename, files[inf].type) do
     if files[inf].filename == filename then
       return inf, true
     end
     inf = inf + 1
-  until inf > sup or system.path_compare(filename, type, files[inf].filename, files[inf].type)
+  end
   return inf, false
 end
 
@@ -1165,8 +1181,8 @@ end
 
 
 -- no-op but can be overrided by plugins
-function core.on_dirmonitor_modify()
-end
+function core.on_dirmonitor_modify() end
+function core.on_dirmonitor_delete() end
 
 
 function core.on_dir_change(watch_id, action, filepath)
@@ -1175,6 +1191,7 @@ function core.on_dir_change(watch_id, action, filepath)
   core.dir_rescan_add_job(dir, filepath)
   if action == "delete" then
     project_scan_remove_file(dir, filepath)
+    core.on_dirmonitor_delete(dir, filepath)
   elseif action == "create" then
     project_scan_add_file(dir, filepath)
     core.on_dirmonitor_modify(dir, filepath);
diff --git a/data/core/tokenizer.lua b/data/core/tokenizer.lua
index d95baeb1..57c17a0b 100644
--- a/data/core/tokenizer.lua
+++ b/data/core/tokenizer.lua
@@ -237,8 +237,13 @@ function tokenizer.tokenize(incoming_syntax, text, state)
 
     -- consume character if we didn't match
     if not matched then
-      push_token(res, "normal", text:sub(i, i))
-      i = i + 1
+      local n = 0
+      -- reach the next character
+      while text:byte(i + n + 1) and common.is_utf8_cont(text, i + n + 1) do
+        n = n + 1
+      end
+      push_token(res, "normal", text:sub(i, i + n))
+      i = i + n + 1
     end
   end
 
diff --git a/data/plugins/language_c.lua b/data/plugins/language_c.lua
index 44c3b895..b0a4dec5 100644
--- a/data/plugins/language_c.lua
+++ b/data/plugins/language_c.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "C",
   files = { "%.c$", "%.h$", "%.inl$" },
   comment = "//",
   patterns = {
diff --git a/data/plugins/language_cpp.lua b/data/plugins/language_cpp.lua
index 499a09db..8d6aef4b 100644
--- a/data/plugins/language_cpp.lua
+++ b/data/plugins/language_cpp.lua
@@ -4,6 +4,7 @@ pcall(require, "plugins.language_c")
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "C++",
   files = {
     "%.h$", "%.inl$", "%.cpp$", "%.cc$", "%.C$", "%.cxx$",
     "%.c++$", "%.hh$", "%.H$", "%.hxx$", "%.hpp$", "%.h++$"
diff --git a/data/plugins/language_css.lua b/data/plugins/language_css.lua
index 222e2f94..395e375c 100644
--- a/data/plugins/language_css.lua
+++ b/data/plugins/language_css.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "CSS",
   files = { "%.css$" },
   patterns = {
     { pattern = "\\.",                type = "normal"   },
diff --git a/data/plugins/language_html.lua b/data/plugins/language_html.lua
index cebb3f1a..1f4515bc 100644
--- a/data/plugins/language_html.lua
+++ b/data/plugins/language_html.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "HTML",
   files = { "%.html?$" },
   patterns = {
     { 
diff --git a/data/plugins/language_js.lua b/data/plugins/language_js.lua
index 7556b00b..291c1287 100644
--- a/data/plugins/language_js.lua
+++ b/data/plugins/language_js.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "JavaScript",
   files = { "%.js$", "%.json$", "%.cson$" },
   comment = "//",
   patterns = {
diff --git a/data/plugins/language_lua.lua b/data/plugins/language_lua.lua
index 165633b6..5c770d43 100644
--- a/data/plugins/language_lua.lua
+++ b/data/plugins/language_lua.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "Lua",
   files = "%.lua$",
   headers = "^#!.*[ /]lua",
   comment = "--",
diff --git a/data/plugins/language_md.lua b/data/plugins/language_md.lua
index 3c1c329a..62cb8a86 100644
--- a/data/plugins/language_md.lua
+++ b/data/plugins/language_md.lua
@@ -4,6 +4,7 @@ local syntax = require "core.syntax"
 
 
 syntax.add {
+  name = "Markdown",
   files = { "%.md$", "%.markdown$" },
   patterns = {
     { pattern = "\\.",                      type = "normal"   },
diff --git a/data/plugins/language_python.lua b/data/plugins/language_python.lua
index 60aa41a6..f1430fb1 100644
--- a/data/plugins/language_python.lua
+++ b/data/plugins/language_python.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "Python",
   files = { "%.py$", "%.pyw$" },
   headers = "^#!.*[ /]python",
   comment = "#",
diff --git a/data/plugins/language_xml.lua b/data/plugins/language_xml.lua
index 95e310bb..c858d3cf 100644
--- a/data/plugins/language_xml.lua
+++ b/data/plugins/language_xml.lua
@@ -2,6 +2,7 @@
 local syntax = require "core.syntax"
 
 syntax.add {
+  name = "XML",
   files = { "%.xml$" },
   headers = "<%?xml",
   patterns = {
diff --git a/data/plugins/lineguide.lua b/data/plugins/lineguide.lua
index 61debbff..41109e4f 100644
--- a/data/plugins/lineguide.lua
+++ b/data/plugins/lineguide.lua
@@ -2,20 +2,22 @@
 local config = require "core.config"
 local style = require "core.style"
 local DocView = require "core.docview"
+local CommandView = require "core.commandview"
 
 local draw_overlay = DocView.draw_overlay
 
 function DocView:draw_overlay(...)
-  local ns = ("n"):rep(config.line_limit)
-  local ss = self:get_font():subpixel_scale()
-  local offset = self:get_font():get_width_subpixel(ns) / ss
-  local x = self:get_line_screen_position(1) + offset
-  local y = self.position.y
-  local w = math.ceil(SCALE * 1)
-  local h = self.size.y
-
-  local color = style.guide or style.selection
-  renderer.draw_rect(x, y, w, h, color)
-
+  if not self:is(CommandView) then
+    local ns = ("n"):rep(config.line_limit)
+    local ss = self:get_font():subpixel_scale()
+    local offset = self:get_font():get_width_subpixel(ns) / ss
+    local x = self:get_line_screen_position(1) + offset
+    local y = self.position.y
+    local w = math.ceil(SCALE * 1)
+    local h = self.size.y
+  
+    local color = style.guide or style.selection
+    renderer.draw_rect(x, y, w, h, color)
+  end
   draw_overlay(self, ...)
 end
diff --git a/data/plugins/treeview.lua b/data/plugins/treeview.lua
index 77b6732f..2909768c 100644
--- a/data/plugins/treeview.lua
+++ b/data/plugins/treeview.lua
@@ -42,6 +42,19 @@ function TreeView:new()
   self.target_size = default_treeview_size
   self.cache = {}
   self.tooltip = { x = 0, y = 0, begin = 0, alpha = 0 }
+  self:add_core_hooks()
+end
+
+
+function TreeView:add_core_hooks()
+  -- When a file or directory is deleted we delete the corresponding cache entry
+  -- because if the entry is recreated we may use wrong information from cache.
+  local on_delete = core.on_dirmonitor_delete
+  core.on_dirmonitor_delete = function(dir, filepath)
+    local cache = self.cache[dir.name]
+    if cache then cache[filepath] = nil end
+    on_delete(dir, filepath)
+  end
 end
 
 
diff --git a/src/api/system.c b/src/api/system.c
index 0ebf78f1..4c14843b 100644
--- a/src/api/system.c
+++ b/src/api/system.c
@@ -723,6 +723,13 @@ static int f_watch_dir(lua_State *L) {
   return 1;
 }
 
+static int f_unwatch_dir(lua_State *L) {
+  dmon_watch_id watch_id;
+  watch_id.id = luaL_checkinteger(L, 1);
+  dmon_unwatch(watch_id);
+  return 0;
+}
+
 #if __linux__
 static int f_watch_dir_add(lua_State *L) {
   dmon_watch_id watch_id;
@@ -826,6 +833,7 @@ static const luaL_Reg lib[] = {
   { "fuzzy_match",         f_fuzzy_match         },
   { "set_window_opacity",  f_set_window_opacity  },
   { "watch_dir",           f_watch_dir           },
+  { "unwatch_dir",         f_unwatch_dir         },
   { "path_compare",        f_path_compare        },
 #if __linux__
   { "watch_dir_add",       f_watch_dir_add       },