diff --git a/src/gui/mainwindow.py b/src/gui/mainwindow.py
--- a/src/gui/mainwindow.py
+++ b/src/gui/mainwindow.py
@@ -1,12 +1,13 @@
 import tkinter as tk
 from tkinter import N,S,E,W
 
-from . import menu
+from .util import MsgMixin
+from .menu import MainMenu
 from .boardview import BoardView
 from .imgview import ImgView
 
 
-class MainWindow(tk.Frame):
+class MainWindow(tk.Frame,MsgMixin):
 	def __init__(self,parent,master=None):
 		self.parent=parent
 
@@ -14,17 +15,13 @@ class MainWindow(tk.Frame):
 		self.grid(column=0,row=0,sticky=(N,S,E,W))
 		self._createWidgets()
 
-		self.bind("<Left>",lambda e: self.sendMsg("prevFrame"))
-		self.bind("<Right>",lambda e: self.sendMsg("nextFrame"))
-
 	def setCurrentFrame(self,frame):
 		self.imgView.setImg(frame)
 
 	def _createWidgets(self):
 		# menu
 		self.parent.root.option_add('*tearOff',False)
-		menubar=menu.createTopBar(self.parent.root)
-		menu.createMainMenu(menubar)
+		self._menu=MainMenu(self.parent,self.parent.root)
 
 		# a captured frame with overlay graphics
 		self._imgWrapper=tk.Frame(self,width=480,height=360)
@@ -37,14 +34,6 @@ class MainWindow(tk.Frame):
 		self.boardView=BoardView(self._boardWrapper)
 		self._boardWrapper.grid(column=1,row=0,sticky=(N,S,E,W))
 
-		# more controls below the board
-		self.scaleTresB=tk.Scale(self, orient=tk.HORIZONTAL, length=200, from_=0.0, to=100.0, command=self.refreshTresholds)
-		self.scaleTresW=tk.Scale(self, orient=tk.HORIZONTAL, length=200, from_=0.0, to=100.0, command=self.refreshTresholds)
-		self.scaleTresB.set(30.0) # !! proper defaults
-		self.scaleTresW.set(60.0)
-		self.scaleTresB.grid(column=0,row=1,columnspan=2)
-		self.scaleTresW.grid(column=0,row=2,columnspan=2)
-
 		self.columnconfigure(0,weight=1)
 		self.columnconfigure(1,weight=1)
 		self.rowconfigure(0,weight=1)
@@ -55,9 +44,3 @@ class MainWindow(tk.Frame):
 	## Redraws the current image and its overlay.
 	def redrawImgView(self):
 		self.imgView.redraw()
-
-	def refreshTresholds(self,_):
-		self.parent.sendMsg("setTresholds",tuple(),{"tresB":self.scaleTresB.get(), "tresW":self.scaleTresW.get()})
-
-	def sendMsg(self,actionName,args=tuple(),kwargs=None):
-		self.parent.sendMsg(actionName,args,kwargs)