diff --git a/Booklet/build/debug/main.js b/Booklet/build/debug/main.js
index 045fba1..4c7ad8a 100644
--- a/Booklet/build/debug/main.js
+++ b/Booklet/build/debug/main.js
@@ -1,5 +1,5 @@
 (function() {
-  var Book, Booklet, BookletChapter, BookletEntry, BookletFile, BookletFolder, BookletSection;
+  var Booklet, BookletBook, BookletChapter, BookletEntry, BookletFile, BookletFolder, BookletSection, NS;
 
   Booklet = class Booklet extends this.OS.GUI.BaseApplication {
     constructor(args) {
@@ -11,13 +11,20 @@
       me = this;
       this.tree = this.find("toc-ui");
       this.currentToc = void 0;
+      this.dirty = false;
       this.emux = false;
       this.on("treeselect", function(e) {
-        console.log(e.treepath);
         if ((me.currentToc === e) || (e === void 0) || (e.treepath === 0)) {
           return me.reloadEditor();
         }
-        return me.open(e);
+        e.treepath = e.path;
+        return me.load(e).then(function() {
+          return me.open(e);
+        }).catch(function(msg) {
+          e.loaded = true;
+          me.open(e);
+          return me.error(__("Error when loading '{0}': {1}", e.name, msg));
+        });
       });
       this.initEditor();
       this.resizeContent();
@@ -40,13 +47,14 @@
         if (!me.currentToc) {
           return;
         }
-        return me.currentToc.descFile.dirty = true;
+        me.currentToc.descFile.dirty = true;
+        return me.dirty = true;
       });
     }
 
     newChapter() {
       var ch;
-      if (!(this.currentToc && this.currentToc.type === "book")) {
+      if (!(this.currentToc && this.currentToc.type === "Book")) {
         return this.error(__("No book selected"));
       }
       ch = new BookletChapter(this.book);
@@ -56,7 +64,7 @@
 
     newSection() {
       var sec;
-      if (!(this.currentToc && this.currentToc.type === "chapter")) {
+      if (!(this.currentToc && this.currentToc.type === "Chapter")) {
         return this.error(__("No chapter selected"));
       }
       sec = new BookletSection(this.currentToc);
@@ -66,7 +74,7 @@
 
     newFile() {
       var file;
-      if (!(this.currentToc && this.currentToc.type === "section")) {
+      if (!(this.currentToc && this.currentToc.type === "Section")) {
         return this.error(__("No section selected"));
       }
       file = new BookletFile(this.currentToc);
@@ -94,12 +102,33 @@
       });
     }
 
+    load(entry) {
+      var me;
+      me = this;
+      return new Promise(function(r, e) {
+        if (entry.loaded) {
+          return r();
+        }
+        return entry.descFile.meta(function(d) {
+          if (d.error) {
+            return e(d.error);
+          }
+          return entry.descFile.read(function(data) {
+            entry.descFile.cache = data;
+            entry.loaded = true;
+            entry.descFile.dirty = false;
+            return r();
+          });
+        });
+      });
+    }
+
     contextMenu() {
       if (!this.currentToc) {
         return void 0;
       }
       switch (this.currentToc.type) {
-        case "book":
+        case "Book":
           return [
             {
               text: __("New chapter"),
@@ -110,7 +139,7 @@
               dataid: "delete"
             }
           ];
-        case "chapter":
+        case "Chapter":
           return [
             {
               text: __("New section"),
@@ -121,7 +150,7 @@
               dataid: "delete"
             }
           ];
-        case "section":
+        case "Section":
           return [
             {
               text: __("New file"),
@@ -132,7 +161,7 @@
               dataid: "delete"
             }
           ];
-        case "file":
+        case "File":
           return [
             {
               text: __("Delete file"),
@@ -267,10 +296,20 @@
       me = this;
       switch (e) {
         case `${this.name}-Open`:
-          return this.openDialog("FileDiaLog", function(d, f) {
-            return console.log(`${d}/${f}`.asFileHandler());
-          }, __("Open file"), {
-            mimes: me.meta().mimes
+          return this.checkForDirty(function() {
+            return me.openDialog("FileDiaLog", function(d, f) {
+              me.book = new BookletBook(d);
+              return me.book.read(d).then(function() {
+                me.book.treepath = me.book.path;
+                me.tree.set("selectedItem", void 0);
+                me.displayToc();
+                return me.notify(__("Book loaded"));
+              }).catch(function(msg) {
+                return me.error(__("Cannot load book: {0}", msg));
+              });
+            }, __("Open file"), {
+              mimes: ['dir']
+            });
           });
         case `${this.name}-New`:
           return this.openDialog("FileDiaLog", function(d, f) {
@@ -290,6 +329,7 @@
           }
           me.displayToc();
           return me.book.save().then(function() {
+            me.dirty = false;
             return me.notify(__("Book saved"));
           }).catch(function(e) {
             return me.error(__("Can't save the book : {0}", e));
@@ -297,18 +337,36 @@
       }
     }
 
-    open(toc) {
-      this.emux = true;
-      this.saveContext();
-      this.currentToc = toc;
-      this.reloadEditor();
-      this.displayToc();
-      return this.emux = false;
+    checkForDirty(f) {
+      if (!this.dirty) {
+        return f();
+      }
+      return this._gui.openDialog("YesNoDialog", function(d) {
+        console.log(d);
+        if (d) {
+          return f();
+        }
+      }, __("Continue ?"), {
+        text: __("Book is unsaved, you want to continue ?")
+      });
     }
 
+    open(toc) {
+      var me;
+      me = this;
+      me.emux = true;
+      me.saveContext();
+      me.currentToc = toc;
+      me.reloadEditor();
+      me.displayToc();
+      return me.emux = false;
+    }
+
+    openBook(metaFile) {}
+
     newAt(folder) {
       this.tree.set("selectedItem", false);
-      this.book = new Book(folder);
+      this.book = new BookletBook(folder);
       this.book.treepath = this.book.path;
       this.currentToc = void 0;
       this.reloadEditor();
@@ -327,8 +385,9 @@
   this.OS.register("Booklet", Booklet);
 
   BookletEntry = class BookletEntry {
-    constructor() {
-      this.name = "Untitled";
+    constructor(name) {
+      this.name = name;
+      this.loaded = true;
     }
 
     save() {}
@@ -346,6 +405,12 @@
       if (!(t && t.length === 2)) {
         return this.name;
       }
+      if (this.hasMeta && this.metaFile) {
+        this.metaFile.dirty = true;
+      }
+      if (this.parent && this.parent.hasMeta && this.parent.metaFile) {
+        this.parent.metaFile.dirty = true;
+      }
       return this.name = t[1].trim();
     }
 
@@ -388,16 +453,20 @@
 
   BookletFolder = class BookletFolder extends BookletEntry {
     constructor(type, path1, hasMeta) {
-      super();
+      super("Untitle");
       this.type = type;
       this.path = path1;
       this.hasMeta = hasMeta;
+      this.init();
+    }
+
+    init() {
       this.cnt = 0;
       this.nodes = [];
       if (this.hasMeta) {
         this.metaFile = `${this.path}/meta.json`.asFileHandler();
       }
-      this.descFile = `${this.path}/INTRO.md`.asFileHandler();
+      return this.descFile = `${this.path}/INTRO.md`.asFileHandler();
     }
 
     add(chap) {
@@ -431,6 +500,49 @@
       });
     }
 
+    read(folderPath) {
+      var me;
+      me = this;
+      return new Promise(function(r, e) {
+        me.path = folderPath;
+        me.init();
+        me.loaded = false;
+        return me.metaFile.meta(function(d) {
+          if (d.error) {
+            return e(d.error);
+          }
+          return me.metaFile.read(function(data) {
+            var fn, i, j, len, list, ref, v;
+            // load all child
+            me.name = data.name;
+            list = [];
+            ref = data.entries;
+            for (i = j = 0, len = ref.length; j < len; i = ++j) {
+              v = ref[i];
+              list[i] = v;
+            }
+            fn = function(l) {
+              var el, obj;
+              if (l.length === 0) {
+                me.cnt = data.cnt;
+                return r();
+              }
+              el = (l.splice(0, 1))[0];
+              console.log("create", el.type);
+              obj = new NS[el.type](me);
+              obj.name = el.name;
+              return obj.read(el.path).then(function() {
+                return fn(l);
+              }).catch(function(msg) {
+                return fn(l);
+              });
+            };
+            return fn(list);
+          }, "json");
+        });
+      });
+    }
+
     size() {
       return this.nodes.length;
     }
@@ -464,7 +576,7 @@
       return new Promise(function(r, e) {
         var i, j, len, list, ref, v;
         list = [];
-        if (me.type !== 'section') {
+        if (me.type !== 'Section') {
           ref = me.nodes;
           for (i = j = 0, len = ref.length; j < len; i = ++j) {
             v = ref[i];
@@ -496,7 +608,7 @@
       var me;
       me = this;
       return new Promise(function(r, e) {
-        var entries, i, j, len, ref, v;
+        var data, entries, i, j, len, ref, v;
         if (!me.metaFile.dirty) {
           return r();
         }
@@ -504,9 +616,19 @@
         ref = me.nodes;
         for (i = j = 0, len = ref.length; j < len; i = ++j) {
           v = ref[i];
-          entries[i] = v.path;
+          entries[i] = {
+            name: v.name,
+            path: v.path,
+            type: v.type
+          };
         }
-        me.metaFile.cache = entries;
+        data = {
+          name: me.name,
+          entries: entries,
+          cnt: me.cnt,
+          meta: me.hasMeta
+        };
+        me.metaFile.cache = data;
         return me.metaFile.write("object", function(d) {
           if (d.error) {
             return e(d.error);
@@ -585,9 +707,9 @@
 
   };
 
-  Book = class Book extends BookletFolder {
+  BookletBook = class BookletBook extends BookletFolder {
     constructor(path) {
-      super('book', path, true);
+      super('Book', path, true);
     }
 
     save() {
@@ -612,7 +734,7 @@
     constructor(book) {
       var path;
       path = `${book.path}/c_${book.cnt}`;
-      super('chapter', path, true);
+      super('Chapter', path, true);
       book.add(this);
     }
 
@@ -622,7 +744,7 @@
     constructor(chapter) {
       var path;
       path = `${chapter.path}/s_${chapter.cnt}`;
-      super("section", path, true);
+      super("Section", path, true);
       chapter.add(this);
     }
 
@@ -630,10 +752,10 @@
 
   BookletFile = class BookletFile extends BookletEntry {
     constructor(section) {
-      super();
+      super("Untitle file");
       this.section = section;
       this.hasMeta = false;
-      this.type = "file";
+      this.type = "File";
       this.path = `${this.section.path}/f_${this.section.cnt}.md`;
       this.descFile = this.path.asFileHandler();
       this.section.add(this);
@@ -657,6 +779,16 @@
       });
     }
 
+    read(p) {
+      var me;
+      me = this;
+      return new Promise(function(r, e) {
+        me.loaded = false;
+        me.treepath = p;
+        return r();
+      });
+    }
+
     toc() {
       this.updateName();
       return this;
@@ -664,4 +796,11 @@
 
   };
 
+  NS = {
+    Book: BookletBook,
+    Chapter: BookletChapter,
+    Section: BookletSection,
+    File: BookletFile
+  };
+
 }).call(this);
diff --git a/Booklet/build/debug/package.json b/Booklet/build/debug/package.json
index 975a4db..2faf808 100644
--- a/Booklet/build/debug/package.json
+++ b/Booklet/build/debug/package.json
@@ -9,5 +9,5 @@
     "version":"0.0.1-a",
     "category":"Other",
     "iconclass":"fa fa-adn",
-    "mimes":["application/json"]
+    "mimes":["dir"]
 }
\ No newline at end of file
diff --git a/Booklet/coffees/common.coffee b/Booklet/coffees/common.coffee
index e922b65..68bdf35 100644
--- a/Booklet/coffees/common.coffee
+++ b/Booklet/coffees/common.coffee
@@ -1,6 +1,7 @@
+
 class BookletEntry
-    constructor: () ->
-        @name = "Untitled"
+    constructor: (@name) ->
+        @loaded = true
         
     save: () ->
     
@@ -13,6 +14,8 @@ class BookletEntry
         return @name unless @descFile.dirty
         t = (new RegExp "^\s*#+(.*)\n", "g").exec @descFile.cache
         return @name unless t and t.length is 2
+        @metaFile.dirty = true if @hasMeta and @metaFile
+        @parent.metaFile.dirty = true if @parent and @parent.hasMeta and @parent.metaFile
         @name =  t[1].trim()
     
     remove: () ->
@@ -35,7 +38,10 @@ class BookletEntry
 
 class BookletFolder extends BookletEntry
     constructor: (@type, @path, @hasMeta) ->
-        super()
+        super "Untitle"
+        @init()
+    
+    init: () ->
         @cnt = 0
         @nodes = []
         @metaFile = "#{@path}/meta.json".asFileHandler() if @hasMeta
@@ -60,7 +66,34 @@ class BookletFolder extends BookletEntry
                 r()
             .catch (msg) ->
                 e msg
-            
+    read: (folderPath) ->
+        me = @
+        return new Promise (r, e) ->
+            me.path = folderPath
+            me.init()
+            me.loaded = false
+            me.metaFile.meta (d) ->
+                return e d.error if d.error
+                me.metaFile.read (data) ->
+                    # load all child
+                    me.name = data.name
+                    list = []
+                    list[i] = v for v,i in data.entries
+                    fn = (l) ->
+                        if l.length is 0
+                            me.cnt = data.cnt
+                            return r() 
+                        el = (l.splice 0, 1)[0]
+                        #console.log "create", el.type
+                        obj = new NS[el.type]( me )
+                        obj.name = el.name
+                        obj.read(el.path).then () ->
+                            fn l
+                        .catch (msg) ->
+                            fn l
+                            
+                    return fn list
+                , "json"
 
     size: () ->
         return @nodes.length
@@ -81,7 +114,7 @@ class BookletFolder extends BookletEntry
         me = @
         return new Promise (r, e) ->
             list = []
-            list[i] = v for v, i in me.nodes if me.type isnt 'section'
+            list[i] = v for v, i in me.nodes if me.type isnt 'Section'
             me.mkdir().then () ->
                 fn = (l) ->
                     return r() if l.length is 0
@@ -98,12 +131,18 @@ class BookletFolder extends BookletEntry
         return new Promise (r, e) ->
             return r() unless me.metaFile.dirty
             entries = []
-            entries[i] = v.path for v,i in me.nodes
-            me.metaFile.cache = entries
+            entries[i] = {name: v.name, path:v.path, type:v.type} for v,i in me.nodes
+            data = {
+                name: me.name,
+                entries: entries,
+                cnt: me.cnt,
+                meta: me.hasMeta
+            }
+            me.metaFile.cache = data
             me.metaFile.write "object", (d) ->
                 return e d.error if d.error
                 me.metaFile.dirty = false
-                console.log "saved " + me.metaFile.path
+                #console.log "saved " + me.metaFile.path
                 r()
             
     
@@ -115,7 +154,7 @@ class BookletFolder extends BookletEntry
                 me.descFile.write "text/plain", (d) ->
                     return e d.error if d.error
                     me.descFile.dirty = false
-                    console.log "saved " + me.descFile.path
+                    #console.log "saved " + me.descFile.path
                     r()
             .catch (msg) -> e msg
                 
@@ -141,9 +180,9 @@ class BookletFolder extends BookletEntry
         @
     
 
-class Book extends BookletFolder
+class BookletBook extends BookletFolder
     constructor: (path) ->
-        super 'book', path, true
+        super 'Book', path, true
         
     save:() ->
         me = @
@@ -158,22 +197,22 @@ class Book extends BookletFolder
 class BookletChapter extends BookletFolder
     constructor: (book) ->
         path = "#{book.path}/c_#{book.cnt}"
-        super 'chapter', path, true
+        super 'Chapter', path, true
         book.add @
                 
 
 class BookletSection extends BookletFolder
     constructor: (chapter) ->
         path = "#{chapter.path}/s_#{chapter.cnt}"
-        super "section", path,  true
+        super "Section", path,  true
         chapter.add @
         
 
 class BookletFile extends BookletEntry
     constructor: (@section) ->
-        super()
+        super "Untitle file"
         @hasMeta = false
-        @type = "file"
+        @type = "File"
         @path = "#{@section.path}/f_#{@section.cnt}.md"
         @descFile = @path.asFileHandler()
         @section.add @
@@ -185,9 +224,22 @@ class BookletFile extends BookletEntry
             me.descFile.write "text/plain", (d) ->
                 return e d.error if d.error
                 me.descFile.dirty = false
-                console.log "saved" + me.descFile.path
+                #console.log "saved" + me.descFile.path
                 r()
     
+    read: (p) ->
+        me = @
+        return new Promise (r, e) ->
+            me.loaded = false
+            me.treepath = p
+            r() 
+    
     toc: () ->
         @updateName()
-        @
\ No newline at end of file
+        @
+
+NS =
+    Book: BookletBook
+    Chapter: BookletChapter
+    Section: BookletSection
+    File: BookletFile
\ No newline at end of file
diff --git a/Booklet/coffees/main.coffee b/Booklet/coffees/main.coffee
index d0a1145..0f35d69 100644
--- a/Booklet/coffees/main.coffee
+++ b/Booklet/coffees/main.coffee
@@ -6,10 +6,17 @@ class Booklet extends this.OS.GUI.BaseApplication
         me = @
         @tree = @find "toc-ui"
         @currentToc = undefined
+        @dirty = false
         @emux = false
         @on "treeselect", (e) ->
             return me.reloadEditor() if (me.currentToc is e) or (e is undefined) or (e.treepath is 0)
-            me.open e
+            e.treepath = e.path
+            me.load(e).then ()->
+                me.open e
+            .catch (msg) ->
+                e.loaded = true
+                me.open e
+                me.error __("Error when loading '{0}': {1}", e.name, msg)
         
         @initEditor()
         @resizeContent()
@@ -24,21 +31,22 @@ class Booklet extends this.OS.GUI.BaseApplication
             return if me.emux
             return unless me.currentToc
             me.currentToc.descFile.dirty = true
+            me.dirty = true
     
     newChapter: () ->
-        return @error __("No book selected") unless @currentToc and @currentToc.type is "book"
+        return @error __("No book selected") unless @currentToc and @currentToc.type is "Book"
         ch = new BookletChapter(@book)
         @displayToc()
         ch.treepath = ch.path
     
     newSection: () ->
-        return @error __("No chapter selected") unless @currentToc and @currentToc.type is "chapter"
+        return @error __("No chapter selected") unless @currentToc and @currentToc.type is "Chapter"
         sec = new BookletSection(@currentToc)
         @displayToc()
         sec.treepath = sec.path
     
     newFile: () ->
-        return @error __("No section selected") unless @currentToc and @currentToc.type is "section"
+        return @error __("No section selected") unless @currentToc and @currentToc.type is "Section"
         file = new BookletFile(@currentToc)
         @displayToc()
         file.treepath = file.path
@@ -57,25 +65,37 @@ class Booklet extends this.OS.GUI.BaseApplication
             me.error e
             fn()
     
+    load: (entry) ->
+        me = @
+        return new Promise (r, e) ->
+            return r() if entry.loaded
+            entry.descFile.meta (d) ->
+                return e d.error if d.error
+                entry.descFile.read (data) ->
+                    entry.descFile.cache = data
+                    entry.loaded = true
+                    entry.descFile.dirty = false
+                    r()
+    
     contextMenu: () ->
         return undefined unless @currentToc
         switch @currentToc.type
-            when "book"
+            when "Book"
                 return [
                     { text: __("New chapter"), dataid: "newChapter" },
                     { text: __("Delete book"), dataid: "delete" }
                 ]
-            when "chapter"
+            when "Chapter"
                 return [
                     { text: __("New section"), dataid: "newSection" },
                     { text: __("Delete chapter"), dataid: "delete" }
                 ]
-            when "section"
+            when "Section"
                 return [
                     { text: __("New file"), dataid: "newFile" },
                     { text: __("Delete section"), dataid: "delete" }
                 ]
-            when "file"
+            when "File"
                 return [
                     { text: __("Delete file"), dataid: "delete" }
                 ]
@@ -157,9 +177,17 @@ class Booklet extends this.OS.GUI.BaseApplication
         me = @
         switch e
             when "#{@name}-Open"
-                @openDialog "FileDiaLog", ( d, f ) ->
-                    console.log "#{d}/#{f}".asFileHandler()
-                , __("Open file"), { mimes: me.meta().mimes }
+                @checkForDirty () ->
+                    me.openDialog "FileDiaLog", ( d, f ) ->
+                        me.book = new BookletBook(d)
+                        me.book.read(d).then () ->
+                            me.book.treepath = me.book.path
+                            me.tree.set "selectedItem", undefined
+                            me.displayToc()
+                            me.notify __("Book loaded")
+                        .catch (msg) ->
+                            me.error __("Cannot load book: {0}", msg)
+                    , __("Open file"), { mimes: ['dir'] }
              when "#{@name}-New"
                 @openDialog "FileDiaLog", ( d, f ) ->
                     me.newAt "#{d}/#{f}"
@@ -169,24 +197,34 @@ class Booklet extends this.OS.GUI.BaseApplication
                 me.saveContext() if me.currentToc
                 me.displayToc()
                 me.book.save().then () ->
+                    me.dirty = false
                     me.notify __("Book saved")
                 .catch (e) ->
                     me.error __("Can't save the book : {0}", e)
     
+    checkForDirty: (f) ->
+        return f() unless @dirty
+        @_gui.openDialog "YesNoDialog", (d) ->
+            # console.log d
+            if d
+                f()
+        , __("Continue ?"), { text: __("Book is unsaved, you want to continue ?") }
+    
     open: (toc) ->
-        @emux = true
-        @saveContext()
-        @currentToc  = toc
-        @reloadEditor()
-        @displayToc()
-        @emux = false
+        me = @
+        me.emux = true
+        me.saveContext()
+        me.currentToc  = toc
+        me.reloadEditor()
+        me.displayToc()
+        me.emux = false
     
     openBook: (metaFile) ->
         
     
     newAt: (folder) ->
         @tree.set "selectedItem", false
-        @book = new Book(folder)
+        @book = new BookletBook(folder)
         @book.treepath = @book.path
         @currentToc = undefined
         @reloadEditor()
diff --git a/Booklet/package.json b/Booklet/package.json
index 975a4db..2faf808 100644
--- a/Booklet/package.json
+++ b/Booklet/package.json
@@ -9,5 +9,5 @@
     "version":"0.0.1-a",
     "category":"Other",
     "iconclass":"fa fa-adn",
-    "mimes":["application/json"]
+    "mimes":["dir"]
 }
\ No newline at end of file
diff --git a/DrawIOWrapper/package.json b/DrawIOWrapper/package.json
index 2cabed6..a3f1421 100644
--- a/DrawIOWrapper/package.json
+++ b/DrawIOWrapper/package.json
@@ -10,4 +10,4 @@
     "category":"Other",
     "iconclass":"fa fa-adn",
     "mimes":["none"]
-}
\ No newline at end of file
+}