diff --git a/dist/index.js b/dist/index.js
index 14a1d33d..861f64ce 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -314,6 +314,22 @@
   function createTimestamp() {
     return (/* @__PURE__ */ new Date()).toISOString();
   }
+  var HandlerManager = class {
+    handlers = /* @__PURE__ */ new Set();
+    // manage
+    addHandler = (handler) => {
+      this.handlers.add(handler);
+    };
+    deleteHandler = (handler) => {
+      this.handlers.delete(handler);
+    };
+    // trigger
+    trigger = (item) => {
+      for (const handler of this.handlers) {
+        handler(item);
+      }
+    };
+  };
   function stringify(data) {
     return JSON.stringify(data, null, 4);
   }
@@ -531,8 +547,7 @@
     storageModel;
     chatModel;
     fileModel;
-    boardHandler = () => {
-    };
+    boardHandlerManager = new HandlerManager();
     // paths
     getBasePath = () => {
       return this.fileModel.getModelContainerPath("taskModel");
@@ -576,9 +591,9 @@
       return boardInfoFileContent;
     };
     updateBoard = (boardInfoFileContent) => {
-      this.boardHandler(boardInfoFileContent);
       this.storeBoard(boardInfoFileContent);
       this.chatModel.sendMessage("", boardInfoFileContent);
+      this.boardHandlerManager.trigger(boardInfoFileContent);
     };
     storeBoard = (boardInfoFileContent) => {
       this.fileModel.addFileContent(boardInfoFileContent);
@@ -642,16 +657,12 @@
       this.storageModel.removeRecursively(taskFilePath);
       this.storageModel.removeRecursively(taskReferencePath);
     };
-    // other
-    setBoardHandler = (handler) => {
-      this.boardHandler = handler;
-    };
     // init
     constructor(storageModel2, chatModel, fileModel) {
       this.chatModel = chatModel;
       this.fileModel = fileModel;
       this.storageModel = storageModel2;
-      fileModel.setFileContentHandler(this.handleFileContent);
+      fileModel.fileContentHandlerManager.addHandler(this.handleFileContent);
     }
     // utility
     static createBoardInfoFileContent = (fileId, name, color) => {
@@ -705,8 +716,7 @@
     chatModel;
     storageModel;
     taskModel;
-    fileContentHandler = () => {
-    };
+    fileContentHandlerManager = new HandlerManager();
     // paths
     getBasePath = () => {
       return StorageModel.getPath(
@@ -740,7 +750,7 @@
       const didStore = this.storeFileContent(fileContent);
       if (didStore == false) return;
       this.taskModel.handleFileContent(fileContent);
-      this.fileContentHandler(fileContent);
+      this.fileContentHandlerManager.trigger(fileContent);
     };
     // methods
     addFileContent = (fileContent) => {
@@ -788,10 +798,6 @@
       );
       return fileContent;
     };
-    // other
-    setFileContentHandler = (handler) => {
-      this.fileContentHandler = handler;
-    };
     // init
     constructor(chatModel, storageModel2) {
       this.chatModel = chatModel;
@@ -911,8 +917,7 @@
     id;
     info;
     color;
-    chatMessageHandler = () => {
-    };
+    chatMessageHandlerManager = new HandlerManager();
     get secondaryChannels() {
       return this.info.secondaryChannels.sort(localeCompare);
     }
@@ -970,7 +975,7 @@
       if (chatMessage.body != "") {
         const messagePath = this.getMessagePath(chatMessage.id);
         this.storageModel.writeStringifiable(messagePath, chatMessage);
-        this.chatMessageHandler(chatMessage);
+        this.chatMessageHandlerManager.trigger(chatMessage);
       }
       this.fileModel.handleStringifiedFileContent(chatMessage.stringifiedFile);
     };
@@ -1020,10 +1025,6 @@
       const dirPath = this.getBasePath();
       this.storageModel.removeRecursively(dirPath);
     };
-    // other
-    setMessageHandler = (handler) => {
-      this.chatMessageHandler = handler;
-    };
     // load
     loadInfo = () => {
       const info = this.storageModel.readStringifiable(
@@ -1439,9 +1440,11 @@
     // init
     constructor(taskModel, storageModel2) {
       this.taskModel = taskModel;
-      taskModel.setBoardHandler((boardInfoFileContent) => {
-        this.showBoard(boardInfoFileContent);
-      });
+      taskModel.boardHandlerManager.addHandler(
+        (boardInfoFileContent) => {
+          this.showBoard(boardInfoFileContent);
+        }
+      );
     }
   };
 
@@ -1492,7 +1495,7 @@
       );
       this.messagePageViewModel = new MessagePageViewModel(this);
       this.settingsPageViewModel = new SettingsPageViewModel(this);
-      chatModel.setMessageHandler((chatMessage) => {
+      chatModel.chatMessageHandlerManager.addHandler((chatMessage) => {
         this.messagePageViewModel.showChatMessage(chatMessage);
       });
       this.loadPageSelection();
diff --git a/src/Model/Chat/chatModel.ts b/src/Model/Chat/chatModel.ts
index 3d3272ce..a489db3a 100644
--- a/src/Model/Chat/chatModel.ts
+++ b/src/Model/Chat/chatModel.ts
@@ -1,14 +1,18 @@
 // this file is responsible for managing chats.
 
-import { DATA_VERSION, ValidObject } from "../Utility/typeSafety";
-import FileModel, { FileContent } from "../Files/fileModel";
-import StorageModel, { filePaths } from "../Global/storageModel";
 import {
+  DATA_VERSION,
+  ValidObject,
+} from "../Utility/typeSafety";
+import FileModel, { FileContent } from "../Files/fileModel";
+import {
+  HandlerManager,
   createTimestamp,
   localeCompare,
   parseValidObject,
   stringify,
 } from "../Utility/utility";
+import StorageModel, { filePaths } from "../Global/storageModel";
 import { decryptString, encryptString } from "../Utility/crypto";
 
 import ChatListModel from "./chatListModel";
@@ -30,7 +34,7 @@ export default class ChatModel {
   info: ChatInfo;
   color: Color;
 
-  chatMessageHandler: (chatMessage: ChatMessage) => void = () => {};
+  chatMessageHandlerManager: HandlerManager<ChatMessage> = new HandlerManager();
 
   get secondaryChannels(): string[] {
     return this.info.secondaryChannels.sort(localeCompare);
@@ -104,7 +108,7 @@ export default class ChatModel {
     if (chatMessage.body != "") {
       const messagePath: string[] = this.getMessagePath(chatMessage.id);
       this.storageModel.writeStringifiable(messagePath, chatMessage);
-      this.chatMessageHandler(chatMessage);
+      this.chatMessageHandlerManager.trigger(chatMessage);
     }
 
     // file
@@ -173,11 +177,6 @@ export default class ChatModel {
     this.storageModel.removeRecursively(dirPath);
   };
 
-  // other
-  setMessageHandler = (handler: (chatMessage: ChatMessage) => void): void => {
-    this.chatMessageHandler = handler;
-  };
-
   // load
   loadInfo = (): void => {
     const info: ChatInfo | null = this.storageModel.readStringifiable(
diff --git a/src/Model/Files/fileModel.ts b/src/Model/Files/fileModel.ts
index b3639668..7076d98e 100644
--- a/src/Model/Files/fileModel.ts
+++ b/src/Model/Files/fileModel.ts
@@ -1,12 +1,13 @@
 // this file is responsible for managing files within chats.
 
 import { DATA_VERSION, ValidObject } from "../Utility/typeSafety";
-import StorageModel, { filePaths } from "../Global/storageModel";
 import {
+  HandlerManager,
   createTimestamp,
   parseValidObject,
   stringify,
 } from "../Utility/utility";
+import StorageModel, { filePaths } from "../Global/storageModel";
 
 import ChatModel from "../Chat/chatModel";
 import TaskModel from "./taskModel";
@@ -18,7 +19,7 @@ export default class FileModel {
 
   taskModel: TaskModel;
 
-  fileContentHandler: (fileContent: FileContent<string>) => void = () => {};
+  fileContentHandlerManager: HandlerManager<FileContent<string>> = new HandlerManager();
 
   // paths
   getBasePath = (): string[] => {
@@ -63,7 +64,7 @@ export default class FileModel {
     if (didStore == false) return;
 
     this.taskModel.handleFileContent(fileContent);
-    this.fileContentHandler(fileContent);
+    this.fileContentHandlerManager.trigger(fileContent);
   };
 
   // methods
@@ -133,11 +134,6 @@ export default class FileModel {
     );
     return fileContent;
   };
-
-  // other
-  setFileContentHandler = (handler: (fileContent: FileContent<string>) => void): void => {
-    this.fileContentHandler = handler;
-  };
   
   // init
   constructor(chatModel: ChatModel, storageModel: StorageModel) {
diff --git a/src/Model/Files/taskModel.ts b/src/Model/Files/taskModel.ts
index 2f443a4e..25327036 100644
--- a/src/Model/Files/taskModel.ts
+++ b/src/Model/Files/taskModel.ts
@@ -8,6 +8,7 @@ import FileModel, { FileContent } from "./fileModel";
 
 import ChatModel from "../Chat/chatModel";
 import { Color } from "../../colors";
+import { HandlerManager } from "../Utility/utility";
 import StorageModel from "../Global/storageModel";
 import { v4 } from "uuid";
 
@@ -16,7 +17,8 @@ export default class TaskModel {
   chatModel: ChatModel;
   fileModel: FileModel;
 
-  boardHandler: (boardInfoFileContent: BoardInfoFileContent) => void = () => {};
+  boardHandlerManager: HandlerManager<BoardInfoFileContent> =
+    new HandlerManager();
 
   // paths
   getBasePath = (): string[] => {
@@ -78,9 +80,9 @@ export default class TaskModel {
   };
 
   updateBoard = (boardInfoFileContent: BoardInfoFileContent): void => {
-    this.boardHandler(boardInfoFileContent);
     this.storeBoard(boardInfoFileContent);
     this.chatModel.sendMessage("", boardInfoFileContent);
+    this.boardHandlerManager.trigger(boardInfoFileContent);
   };
 
   storeBoard = (boardInfoFileContent: BoardInfoFileContent): void => {
@@ -163,13 +165,6 @@ export default class TaskModel {
     this.storageModel.removeRecursively(taskReferencePath);
   };
 
-  // other
-  setBoardHandler = (
-    handler: (boardInfoFileContent: BoardInfoFileContent) => void
-  ): void => {
-    this.boardHandler = handler;
-  };
-
   // init
   constructor(
     storageModel: StorageModel,
@@ -181,7 +176,7 @@ export default class TaskModel {
     this.storageModel = storageModel;
 
     // handlers
-    fileModel.setFileContentHandler(this.handleFileContent);
+    fileModel.fileContentHandlerManager.addHandler(this.handleFileContent);
   }
 
   // utility
diff --git a/src/Model/Utility/utility.ts b/src/Model/Utility/utility.ts
index 8b3a9f5a..37ff00c0 100644
--- a/src/Model/Utility/utility.ts
+++ b/src/Model/Utility/utility.ts
@@ -5,6 +5,29 @@ export function createTimestamp(): string {
   return new Date().toISOString();
 }
 
+// handlers
+export type Handler<T> = (item: T) => void;
+
+export class HandlerManager<T> {
+  handlers: Set<Handler<T>> = new Set();
+
+  // manage
+  addHandler = (handler: Handler<T>): void => {
+    this.handlers.add(handler);
+  };
+
+  deleteHandler = (handler: Handler<T>): void => {
+    this.handlers.delete(handler);
+  };
+
+  // trigger
+  trigger = (item: T): void => {
+    for (const handler of this.handlers) {
+      handler(item);
+    }
+  };
+}
+
 // string
 export function stringify(data: any): string {
   return JSON.stringify(data, null, 4);
diff --git a/src/ViewModel/Chat/chatViewModel.ts b/src/ViewModel/Chat/chatViewModel.ts
index 02cbad1b..e9ebab07 100644
--- a/src/ViewModel/Chat/chatViewModel.ts
+++ b/src/ViewModel/Chat/chatViewModel.ts
@@ -74,7 +74,7 @@ export default class ChatViewModel {
     this.settingsPageViewModel = new SettingsPageViewModel(this);
 
     // handlers
-    chatModel.setMessageHandler((chatMessage: ChatMessage) => {
+    chatModel.chatMessageHandlerManager.addHandler((chatMessage: ChatMessage) => {
       this.messagePageViewModel.showChatMessage(chatMessage);
     });
 
diff --git a/src/ViewModel/Pages/taskPageViewModel.ts b/src/ViewModel/Pages/taskPageViewModel.ts
index e568787d..3e19c415 100644
--- a/src/ViewModel/Pages/taskPageViewModel.ts
+++ b/src/ViewModel/Pages/taskPageViewModel.ts
@@ -70,8 +70,10 @@ export default class TaskPageViewModel {
     this.taskModel = taskModel;
 
     // handlers
-    taskModel.setBoardHandler((boardInfoFileContent: BoardInfoFileContent) => {
-      this.showBoard(boardInfoFileContent);
-    });
+    taskModel.boardHandlerManager.addHandler(
+      (boardInfoFileContent: BoardInfoFileContent) => {
+        this.showBoard(boardInfoFileContent);
+      }
+    );
   }
 }