diff --git a/fixtracks/detectionmerge.py b/fixtracks/detectionmerge.py
index 4cfd1a2..b0adad6 100644
--- a/fixtracks/detectionmerge.py
+++ b/fixtracks/detectionmerge.py
@@ -1,7 +1,7 @@
 import logging
 
-from PyQt6.QtWidgets import QWidget, QGridLayout, QVBoxLayout, QLabel, QPushButton, QComboBox, QSizePolicy, QSpinBox, QGraphicsView, QGraphicsScene
-from PyQt6.QtCore import QThreadPool, QLineF, QPointF
+from PyQt6.QtWidgets import QWidget, QGridLayout, QVBoxLayout, QLabel, QPushButton, QComboBox, QSizePolicy, QSpinBox, QGraphicsView, QGraphicsScene, QGraphicsLineItem
+from PyQt6.QtCore import QThreadPool, QLineF, QPointF, QRectF, Qt
 from PyQt6.QtGui import QImage, QPixmap, QColor, QPen
 
 from fixtracks.util import ImageReader
@@ -18,6 +18,8 @@ class MergeDetections(QWidget):
         layout = QVBoxLayout()
         layout.addWidget(QLabel("Merge Detections!"))
 
+        self.line_pen = QPen(QColor.fromString("red"), 4)  
+
         self.left_datacombo = QComboBox()
         self.left_videocombo = QComboBox()
         self.left_datacombo.addItems(self._files)
@@ -27,6 +29,7 @@ class MergeDetections(QWidget):
         self.left_preview = QGraphicsView()
         self.left_preview.setSizePolicy(QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Expanding)
         self.left_line = None
+        self.scene = None
 
         self.right_datacombo = QComboBox()
         self.right_videocombo = QComboBox()
@@ -45,7 +48,9 @@ class MergeDetections(QWidget):
         splitter.setColumnStretch(0, 1)
         splitter.setColumnStretch(1, 1)
         layout.addLayout(splitter)
+        
         self.setLayout(layout)
+        
 
     def layout_controls(self):
         grd = QGridLayout()
@@ -134,22 +139,33 @@ class MergeDetections(QWidget):
         height, width, _ = frame.shape
         bytesPerLine = 3 * width
         img = QImage(frame.data, width, height, bytesPerLine, QImage.Format.Format_BGR888).rgbSwapped()
-        scene = QGraphicsScene()
-        scene.addPixmap(QPixmap.fromImage(img).scaledToHeight(self.left_preview.height()))
-        self.left_preview.setScene(scene)
+        self.scene = QGraphicsScene()
+        self._left_pixmap = self.scene.addPixmap(QPixmap.fromImage(img))
+        self.left_preview.setScene(self.scene)
+        self.left_preview.fitInView(self.scene.sceneRect(), mode=Qt.AspectRatioMode.KeepAspectRatio)
+        
         # self.left_preview.setPixmap(QPixmap.fromImage(img).scaledToHeight(self.left_preview.height()))
         self.left_posspinner.setMaximum(width-1)
         self.left_posspinner.setValue(width-1)
-        origin = self.left_preview.mapToScene(int(width//2), 0)
-        destination = self.left_preview.mapToScene(width//2, height)
-        line = QLineF(origin, destination)
-        p = QPen(5)
-        c = QColor.fromString("red")
-        p.setColor(c)
-        self.left_line = scene.addLine(line, p)
+        image_rect = self._left_pixmap.boundingRect()
+
+        x = self.left_posspinner.value()
+        start_x = image_rect.left() +  x 
+        start_y = image_rect.top()
+        end_y = image_rect.bottom()
+
+        self.left_line = self.scene.addLine(start_x, start_y, start_x, end_y, self.line_pen)
         self.left_preview.show()
 
     def on_leftmergelinemove(self):
-        print(self.left_posspinner.value())
-        if self.left_line is not None:
-            self.left_line.setX(self.left_posspinner.value())
\ No newline at end of file
+        image_rect = self._left_pixmap.boundingRect()
+        for i in self.scene.items():
+            if isinstance(i, QGraphicsLineItem):
+                self.scene.removeItem(i)
+
+        x = self.left_posspinner.value()
+        start_x = image_rect.left() +  x 
+        start_y = image_rect.top()
+        end_y = image_rect.bottom()
+
+        self.scene.addLine(start_x, start_y, start_x, end_y, self.line_pen)