diff --git a/src/gui/settings.py b/src/gui/settings.py
--- a/src/gui/settings.py
+++ b/src/gui/settings.py
@@ -1,14 +1,12 @@
 import tkinter as tk
 from tkinter import N,S,E,W,LEFT
 
-from .util import MsgMixin
-
 
-class Settings(tk.Toplevel,MsgMixin):
-	def __init__(self,parent):
-		self.parent=parent
+class Settings(tk.Toplevel):
+	def __init__(self,gui):
+		self._gui=gui
 
-		tk.Toplevel.__init__(self, parent.root)
+		tk.Toplevel.__init__(self, gui.root)
 
 		self.title("Settings | OneEye")
 
@@ -17,9 +15,9 @@ class Settings(tk.Toplevel,MsgMixin):
 		self.content.grid(column=0,row=0,sticky=(N,S,E,W))
 		self.content.columnconfigure(0,weight=1)
 		self._create()
-		self.parent.settings=self
-		self.parent.root.event_generate("<<setUp>>")
-		self.parent.sendMsg("fetchParams")
+		self._gui.settings=self
+		self._gui.root.event_generate("<<setUp>>")
+		self._gui.sendMsg("fetchParams")
 
 	def _create(self):
 		self.scaleTresB=tk.Scale(self.content, orient=tk.HORIZONTAL, length=200, from_=0.0, to=100.0, command=self.refreshTresholds)
@@ -40,14 +38,15 @@ class Settings(tk.Toplevel,MsgMixin):
 		self.cancelButton.pack(side=LEFT)
 
 	def refreshTresholds(self,_):
-		params=self.parent.detector.params
+		params=self._gui.detector.params
 		params.tresB=self.scaleTresB.get()
 		params.tresW=self.scaleTresW.get()
+		self._gui.preview()
 
 	def setParams(self,params):
 		self.scaleTresB.set(params.tresB)
 		self.scaleTresW.set(params.tresW)
 
 	def sendParams(self):
-		self.parent.sendParams()
+		self._gui.sendParams()
 		self.destroy()