diff --git a/data/core/commands/core.lua b/data/core/commands/core.lua
index c8233062..18b76bc9 100644
--- a/data/core/commands/core.lua
+++ b/data/core/commands/core.lua
@@ -95,11 +95,20 @@ command.add(nil, {
     end, function (text)
       return common.home_encode_list(common.path_suggest(common.home_expand(text)))
     end, nil, function(text)
-      local path_stat, err = system.get_file_info(common.home_expand(text))
+      local filename = common.home_expand(text)
+      local path_stat, err = system.get_file_info(filename)
       if err then
-        core.error("Cannot open file %q: %q", text, err)
-      elseif path_stat.type == 'dir' then 
-        core.error("Cannot open %q, is a folder", text)
+        if err:find("No such file", 1, true) then
+          -- check if the containing directory exists
+          local dirname = common.dirname(filename)
+          local dir_stat = dirname and system.get_file_info(dirname)
+          if not dirname or (dir_stat and dir_stat.type == 'dir') then
+            return true
+          end
+        end
+        core.error("Cannot open file %s: %s", text, err)
+      elseif path_stat.type == 'dir' then
+        core.error("Cannot open %s, is a folder", text)
       else
         return true
       end
diff --git a/data/core/commands/doc.lua b/data/core/commands/doc.lua
index 965f3451..9b6ba9af 100644
--- a/data/core/commands/doc.lua
+++ b/data/core/commands/doc.lua
@@ -68,7 +68,12 @@ end
 
 
 local function save(filename)
-  doc():save(filename and core.normalize_to_project_dir(filename))
+  local abs_filename
+  if filename then
+    filename = core.normalize_to_project_dir(filename)
+    abs_filename = core.project_absolute_path(filename)
+  end
+  doc():save(filename, abs_filename)
   local saved_filename = doc().filename
   core.on_doc_save(saved_filename)
   core.log("Saved \"%s\"", saved_filename)
@@ -323,12 +328,14 @@ local commands = {
     end
     core.command_view:set_text(old_filename)
     core.command_view:enter("Rename", function(filename)
-      doc():save(filename)
+      save(common.home_expand(filename))
       core.log("Renamed \"%s\" to \"%s\"", old_filename, filename)
       if filename ~= old_filename then
         os.remove(old_filename)
       end
-    end, common.path_suggest)
+    end, function (text)
+      return common.home_encode_list(common.path_suggest(common.home_expand(text)))
+    end)
   end,
 }
 
diff --git a/data/core/common.lua b/data/core/common.lua
index 022dd1dc..b47cdbbb 100644
--- a/data/core/common.lua
+++ b/data/core/common.lua
@@ -203,6 +203,12 @@ function common.basename(path)
 end
 
 
+-- can return nil if there is no directory part in the path
+function common.dirname(path)
+  return path:match("(.+)[\\/][^\\/]+$")
+end
+
+
 function common.home_encode(text)
   if HOME and string.find(text, HOME, 1, true) == 1 then
     local dir_pos = #HOME + 1
@@ -228,16 +234,6 @@ function common.home_expand(text)
 end
 
 
-function common.normalize_path(filename)
-  if PATHSEP == '\\' then
-    filename = filename:gsub('[/\\]', '\\')
-    local drive, rem = filename:match('^([a-zA-Z])(:.*)')
-    return drive and drive:upper() .. rem or filename
-  end
-  return filename
-end
-
-
 local function split_on_slash(s, sep_pattern)
   local t = {}
   for fragment in string.gmatch(s, "([^/\\]+)") do
@@ -247,8 +243,27 @@ local function split_on_slash(s, sep_pattern)
 end
 
 
+function common.normalize_path(filename)
+  if PATHSEP == '\\' then
+    filename = filename:gsub('[/\\]', '\\')
+    local drive, rem = filename:match('^([a-zA-Z])(:.*)')
+    filename = drive and drive:upper() .. rem or filename
+  end
+  local parts = split_on_slash(filename, PATHSEP)
+  local accu = {}
+  for _, part in ipairs(parts) do
+    if part == '..' then
+      table.remove(accu)
+    elseif part ~= '.' then
+      table.insert(accu, part)
+    end
+  end
+  return table.concat(accu, PATHSEP)
+end
+
+
 function common.path_belongs_to(filename, path)
-  return filename and string.find(filename, path .. PATHSEP, 1, true) == 1
+  return string.find(filename, path .. PATHSEP, 1, true) == 1
 end
 
 
diff --git a/data/core/doc/init.lua b/data/core/doc/init.lua
index 39fae9ca..ca41cdad 100644
--- a/data/core/doc/init.lua
+++ b/data/core/doc/init.lua
@@ -36,10 +36,14 @@ local function splice(t, at, remove, insert)
 end
 
 
-function Doc:new(filename)
+function Doc:new(filename, abs_filename, new_file)
+  self.new_file = new_file
   self:reset()
   if filename then
-    self:load(filename)
+    self:set_filename(filename, abs_filename)
+    if not new_file then
+      self:load(filename)
+    end
   end
 end
 
@@ -65,16 +69,15 @@ function Doc:reset_syntax()
 end
 
 
-function Doc:set_filename(filename)
+function Doc:set_filename(filename, abs_filename)
   self.filename = filename
-  self.abs_filename = system.absolute_path(filename)
+  self.abs_filename = abs_filename
 end
 
 
 function Doc:load(filename)
   local fp = assert( io.open(filename, "rb") )
   self:reset()
-  self:set_filename(filename)
   self.lines = {}
   for line in fp:lines() do
     if line:byte(-1) == 13 then
@@ -91,17 +94,20 @@ function Doc:load(filename)
 end
 
 
-function Doc:save(filename)
-  filename = filename or assert(self.filename, "no filename set to default to")
+function Doc:save(filename, abs_filename)
+  if not filename then
+    assert(self.filename, "no filename set to default to")
+    filename = self.filename
+    abs_filename = self.abs_filename
+  end
   local fp = assert( io.open(filename, "wb") )
   for _, line in ipairs(self.lines) do
     if self.crlf then line = line:gsub("\n", "\r\n") end
     fp:write(line)
   end
   fp:close()
-  if filename then
-    self:set_filename(filename)
-  end
+  self:set_filename(filename, abs_filename)
+  self.new_file = false
   self:reset_syntax()
   self:clean()
 end
@@ -113,7 +119,7 @@ end
 
 
 function Doc:is_dirty()
-  return self.clean_change_id ~= self:get_change_id()
+  return self.clean_change_id ~= self:get_change_id() or self.new_file
 end
 
 
diff --git a/data/core/init.lua b/data/core/init.lua
index 96187167..f008004c 100644
--- a/data/core/init.lua
+++ b/data/core/init.lua
@@ -733,10 +733,30 @@ function core.normalize_to_project_dir(filename)
 end
 
 
+-- The function below works like system.absolute_path except it
+-- doesn't fail if the file does not exist. We consider that the
+-- current dir is core.project_dir so relative filename are considered
+-- to be in core.project_dir.
+-- Please note that .. or . in the filename are not taken into account.
+-- This function should get only filenames normalized using
+-- common.normalize_path function.
+function core.project_absolute_path(filename)
+  if filename:match('^%a:\\') or filename:find('/', 1, true) then
+    return filename
+  else
+    return core.project_dir .. PATHSEP .. filename
+  end
+end
+
+
 function core.open_doc(filename)
+  local new_file = not filename or not system.get_file_info(filename)
+  local abs_filename
   if filename then
+    -- normalize filename and set absolute filename then
     -- try to find existing doc for filename
-    local abs_filename = system.absolute_path(filename)
+    filename = core.normalize_to_project_dir(filename)
+    abs_filename = core.project_absolute_path(filename)
     for _, doc in ipairs(core.docs) do
       if doc.abs_filename and abs_filename == doc.abs_filename then
         return doc
@@ -744,8 +764,7 @@ function core.open_doc(filename)
     end
   end
   -- no existing doc for filename; create new
-  filename = filename and core.normalize_to_project_dir(filename)
-  local doc = Doc(filename)
+  local doc = Doc(filename, abs_filename, new_file)
   table.insert(core.docs, doc)
   core.log_quiet(filename and "Opened doc \"%s\"" or "Opened new doc", filename)
   return doc