diff --git a/bec_widgets/qt_utils/crosshair.py b/bec_widgets/qt_utils/crosshair.py
index 1185da7b..82c80adf 100644
--- a/bec_widgets/qt_utils/crosshair.py
+++ b/bec_widgets/qt_utils/crosshair.py
@@ -11,7 +11,14 @@ class Crosshair(QObject):
     coordinatesChanged2D = pyqtSignal(float, float)
     coordinatesClicked2D = pyqtSignal(float, float)
 
-    def __init__(self, plot_item, precision=None, parent=None):
+    def __init__(self, plot_item: pg.PlotItem, precision: int = None, parent=None):
+        """
+        Crosshair for 1D and 2D plots.
+        Args:
+            plot_item (pyqtgraph.PlotItem): The plot item to which the crosshair will be attached.
+            precision (int, optional): Number of decimal places to round the coordinates to. Defaults to None.
+            parent (QObject, optional): Parent object for the QObject. Defaults to None.
+        """
         super().__init__(parent)
         self.is_log_y = None
         self.is_log_x = None
@@ -26,61 +33,93 @@ class Crosshair(QObject):
         )
         self.plot_item.scene().sigMouseClicked.connect(self.mouse_clicked)
 
-        # Add marker for clicked and selected point
-        data = self.get_data()
-        if isinstance(data, list):  # 1D plot
-            num_curves = len(data)
-            self.marker_moved_1d = []
-            self.marker_clicked_1d = []
-            for i in range(num_curves):
-                color = plot_item.listDataItems()[i].opts["pen"].color()
+        # Initialize markers
+        self.marker_moved_1d = []
+        self.marker_clicked_1d = []
+        self.marker_2d = None
+        self.update_markers()
+
+    def update_markers(self):
+        """Update the markers for the crosshair, creating new ones if necessary."""
+
+        # Clear existing markers
+        for marker in self.marker_moved_1d + self.marker_clicked_1d:
+            self.plot_item.removeItem(marker)
+        if self.marker_2d:
+            self.plot_item.removeItem(self.marker_2d)
+
+        # Create new markers
+        self.marker_moved_1d = []
+        self.marker_clicked_1d = []
+        self.marker_2d = None
+        for item in self.plot_item.items:
+            if isinstance(item, pg.PlotDataItem):  # 1D plot
+                pen = item.opts["pen"]
+                color = pen.color() if hasattr(pen, "color") else pg.mkColor(pen)
                 marker_moved = pg.ScatterPlotItem(
                     size=10, pen=pg.mkPen(color), brush=pg.mkBrush(None)
-                )  # Hollow
+                )
                 marker_clicked = pg.ScatterPlotItem(
                     size=10, pen=pg.mkPen(None), brush=pg.mkBrush(color)
-                )  # Full
+                )
                 self.marker_moved_1d.append(marker_moved)
                 self.marker_clicked_1d.append(marker_clicked)
                 self.plot_item.addItem(marker_moved)
                 self.plot_item.addItem(marker_clicked)
-        else:  # 2D plot
-            self.marker_2d = pg.ROI([0, 0], size=[1, 1], pen=pg.mkPen("r", width=2), movable=False)
-            self.plot_item.addItem(self.marker_2d)
+            elif isinstance(item, pg.ImageItem):  # 2D plot
+                self.marker_2d = pg.ROI(
+                    [0, 0], size=[1, 1], pen=pg.mkPen("r", width=2), movable=False
+                )
+                self.plot_item.addItem(self.marker_2d)
 
-    def get_data(self):
-        curves = []
+    def snap_to_data(self, x, y) -> tuple:
+        """
+        Finds the nearest data points to the given x and y coordinates.
+
+        Args:
+            x: The x-coordinate
+            y: The y-coordinate
+
+        Returns:
+            tuple: The nearest x and y values
+        """
+        y_values_1d = []
+        x_values_1d = []
+        image_2d = None
+
+        # Iterate through items in the plot
         for item in self.plot_item.items:
             if isinstance(item, pg.PlotDataItem):  # 1D plot
-                curves.append((item.xData, item.yData))
+                x_data, y_data = item.xData, item.yData
+                if x_data is not None and y_data is not None:
+                    if self.is_log_x:
+                        min_x_data = np.min(x_data[x_data > 0])
+                    else:
+                        min_x_data = np.min(x_data)
+                    max_x_data = np.max(x_data)
+                    if x < min_x_data or x > max_x_data:
+                        return None, None
+                    closest_x, closest_y = self.closest_x_y_value(x, x_data, y_data)
+                    y_values_1d.append(closest_y)
+                    x_values_1d.append(closest_x)
             elif isinstance(item, pg.ImageItem):  # 2D plot
-                return item.image, None
+                image_2d = item.image
 
-        return curves
+        # Handle 1D plot
+        if y_values_1d:
+            if all(v is None for v in x_values_1d) or all(v is None for v in y_values_1d):
+                return None, None
+            return x, y_values_1d
 
-        # if curves:
-        #     return curves
-        # else:
-        #     return None
-
-    def snap_to_data(self, x, y):
-        data = self.get_data()
-        # if data is None: #TODO hadle if data are None
-        #     return x, y
-
-        if isinstance(data, list):  # 1D plot
-            y_values = []
-            for x_data, y_data in data:
-                closest_x, closest_y = self.closest_x_y_value(x, x_data, y_data)
-                y_values.append(closest_y)
-            return x, y_values
-        elif isinstance(data[0], np.ndarray):  # 2D plot
-            x_idx = int(np.clip(x, 0, data[0].shape[0] - 1))
-            y_idx = int(np.clip(y, 0, data[0].shape[1] - 1))
+        # Handle 2D plot
+        if image_2d is not None:
+            x_idx = int(np.clip(x, 0, image_2d.shape[0] - 1))
+            y_idx = int(np.clip(y, 0, image_2d.shape[1] - 1))
             return x_idx, y_idx
-        return x, y
 
-    def closest_x_y_value(self, input_value, list_x, list_y):
+        return None, None
+
+    def closest_x_y_value(self, input_value: float, list_x: list, list_y: list) -> tuple:
         """
         Find the closest x and y value to the input value.
 
@@ -97,6 +136,11 @@ class Crosshair(QObject):
         return list_x[i], list_y[i]
 
     def mouse_moved(self, event):
+        """Handles the mouse moved event, updating the crosshair position and emitting signals.
+
+        Args:
+            event: The mouse moved event
+        """
         self.check_log()
         pos = event[0]
         if self.plot_item.vb.sceneBoundingRect().contains(pos):
@@ -111,44 +155,61 @@ class Crosshair(QObject):
                 y = 10**y
             x, y_values = self.snap_to_data(x, y)
 
-            if isinstance(y_values, list):  # 1D plot
-                self.coordinatesChanged1D.emit(
-                    round(x, self.precision), [round(y_val, self.precision) for y_val in y_values]
-                )
-                for i, y_val in enumerate(y_values):
-                    self.marker_moved_1d[i].setData(
-                        [x if not self.is_log_x else np.log10(x)],
-                        [y_val if not self.is_log_y else np.log10(y_val)],
+            for item in self.plot_item.items:
+                if isinstance(item, pg.PlotDataItem):
+                    if x is None or all(v is None for v in y_values):
+                        return
+                    self.coordinatesChanged1D.emit(
+                        round(x, self.precision),
+                        [round(y_val, self.precision) for y_val in y_values],
                     )
-            else:  # 2D plot
-                self.coordinatesChanged2D.emit(x, y_values)
+                    for i, y_val in enumerate(y_values):
+                        self.marker_moved_1d[i].setData(
+                            [x if not self.is_log_x else np.log10(x)],
+                            [y_val if not self.is_log_y else np.log10(y_val)],
+                        )
+                elif isinstance(item, pg.ImageItem):
+                    if x is None or y_values is None:
+                        return
+                    self.coordinatesChanged2D.emit(x, y_values)
 
     def mouse_clicked(self, event):
+        """Handles the mouse clicked event, updating the crosshair position and emitting signals.
+
+        Args:
+            event: The mouse clicked event
+        """
         self.check_log()
         if self.plot_item.vb.sceneBoundingRect().contains(event._scenePos):
             mouse_point = self.plot_item.vb.mapSceneToView(event._scenePos)
             x, y = mouse_point.x(), mouse_point.y()
+
             if self.is_log_x:
                 x = 10**x
             if self.is_log_y:
                 y = 10**y
             x, y_values = self.snap_to_data(x, y)
-            if isinstance(y_values, list):  # 1D plot
-                self.coordinatesClicked1D.emit(
-                    round(x, self.precision), [round(y_val, self.precision) for y_val in y_values]
-                )
-                for i, y_val in enumerate(y_values):
-                    self.marker_clicked_1d[i].setData(
-                        [x if not self.is_log_x else np.log10(x)],
-                        [y_val if not self.is_log_y else np.log10(y_val)],
+
+            for item in self.plot_item.items:
+                if isinstance(item, pg.PlotDataItem):
+                    if x is None or all(v is None for v in y_values):
+                        return
+                    self.coordinatesClicked1D.emit(
+                        round(x, self.precision),
+                        [round(y_val, self.precision) for y_val in y_values],
                     )
-            else:  # 2D plot
-                self.coordinatesClicked2D.emit(x, y_values)
-                self.marker_2d.setPos([x, y_values])
+                    for i, y_val in enumerate(y_values):
+                        self.marker_clicked_1d[i].setData(
+                            [x if not self.is_log_x else np.log10(x)],
+                            [y_val if not self.is_log_y else np.log10(y_val)],
+                        )
+                elif isinstance(item, pg.ImageItem):
+                    if x is None or y_values is None:
+                        return
+                    self.coordinatesClicked2D.emit(x, y_values)
+                    self.marker_2d.setPos([x, y_values])
 
     def check_log(self):
-        """
-        Check if x or y axis is in log scale
-        """
+        """Checks if the x or y axis is in log scale and updates the internal state accordingly."""
         self.is_log_x = self.plot_item.ctrl.logXCheck.isChecked()
         self.is_log_y = self.plot_item.ctrl.logYCheck.isChecked()
diff --git a/bec_widgets/qt_utils/utils_example.py b/bec_widgets/qt_utils/utils_example.py
index cca82215..f15ed110 100644
--- a/bec_widgets/qt_utils/utils_example.py
+++ b/bec_widgets/qt_utils/utils_example.py
@@ -8,6 +8,7 @@ from PyQt5.QtWidgets import (
     QHBoxLayout,
     QTableWidget,
     QTableWidgetItem,
+    QSpinBox,
 )
 from pyqtgraph import mkPen
 from pyqtgraph.Qt import QtCore
@@ -40,25 +41,15 @@ class ExampleApp(QWidget):
 
         # same convention as in line_plot.py
         self.y_value_list = [
-            np.sin(self.x_data),
-            np.cos(self.x_data),
-            np.sin(2 * self.x_data),
+            gauss(self.x_data, 1, 1),
+            gauss(self.x_data, 1.5, 3),
+            abs(np.sin(self.x_data)),
+            abs(np.cos(self.x_data)),
+            abs(np.sin(2 * self.x_data)),
         ]  # List of y-values for multiple curves
 
-        self.y_value_list = [gauss(self.x_data, 1, 1), gauss(self.x_data, 1.5, 3)]
-        self.curve_names = ["Gauss(1,1)", "Gauss(1.5,3)"]  # ,"Sine", "Cosine", "Sine2x"]
-
-        # Curves
-        color_list = ["#384c6b", "#e28a2b", "#5E3023", "#e41a1c", "#984e83", "#4daf4a"]
-        self.plot_item_1d.addLegend()
+        self.curve_names = ["Gauss(1,1)", "Gauss(1.5,3)", "Abs(Sine)", "Abs(Cosine)", "Abs(Sine2x)"]
         self.curves = []
-        for ii, y_value in enumerate(self.y_value_list):
-            pen = mkPen(color=color_list[ii], width=2, style=QtCore.Qt.DashLine)
-            curve = pg.PlotDataItem(
-                self.x_data, y_value, pen=pen, skipFiniteCheck=True, name=self.curve_names[ii]
-            )
-            self.plot_item_1d.addItem(curve)
-            self.curves.append(curve)
 
         ##########################
         # 2D Plot
@@ -78,24 +69,13 @@ class ExampleApp(QWidget):
         self.table.resizeColumnsToContents()
 
         ##########################
-        # Signals & Cross-hairs
+        # Spinbox for N curves
         ##########################
-        # 1D
-        self.crosshair_1d = Crosshair(self.plot_item_1d, precision=4)
-        self.crosshair_1d.coordinatesChanged1D.connect(
-            lambda x, y: self.update_table(self.table, x, y, column=0)
-        )
-        self.crosshair_1d.coordinatesClicked1D.connect(
-            lambda x, y: self.update_table(self.table, x, y, column=1)
-        )
-        # 2D
-        self.crosshair_2d = Crosshair(self.plot_item_2d)
-        self.crosshair_2d.coordinatesChanged2D.connect(
-            lambda x, y: self.moved_label_2d.setText(f"Mouse Moved Coordinates (2D): x={x}, y={y}")
-        )
-        self.crosshair_2d.coordinatesClicked2D.connect(
-            lambda x, y: self.clicked_label_2d.setText(f"Clicked Coordinates (2D): x={x}, y={y}")
-        )
+        self.spin_box = QSpinBox()
+        self.spin_box.setMinimum(0)
+        self.spin_box.setMaximum(len(self.y_value_list))
+        self.spin_box.setValue(2)
+        self.spin_box.valueChanged.connect(lambda: self.update_curves(self.spin_box.value()))
 
         ##########################
         # Adding widgets to layout
@@ -105,6 +85,12 @@ class ExampleApp(QWidget):
         self.column1 = QVBoxLayout()
         self.layout.addLayout(self.column1)
 
+        # SpinBox
+        self.spin_row = QHBoxLayout()
+        self.column1.addLayout(self.spin_row)
+        self.spin_row.addWidget(QLabel("Number of curves:"))
+        self.spin_row.addWidget(self.spin_box)
+
         # label
         self.clicked_label_1d = QLabel("Clicked Coordinates (1D):")
         self.column1.addWidget(self.clicked_label_1d)
@@ -128,12 +114,53 @@ class ExampleApp(QWidget):
         # 2D plot
         self.column2.addWidget(self.plot_widget_2d)
 
+        self.update_curves(2)  # just Gaussian curves
+
+    def hook_crosshair(self):
+        self.crosshair_1d = Crosshair(self.plot_item_1d, precision=10)
+        self.crosshair_1d.coordinatesChanged1D.connect(
+            lambda x, y: self.update_table(self.table, x, y, column=0)
+        )
+        self.crosshair_1d.coordinatesClicked1D.connect(
+            lambda x, y: self.update_table(self.table, x, y, column=1)
+        )
+        # 2D
+        self.crosshair_2d = Crosshair(self.plot_item_2d)
+        self.crosshair_2d.coordinatesChanged2D.connect(
+            lambda x, y: self.moved_label_2d.setText(f"Mouse Moved Coordinates (2D): x={x}, y={y}")
+        )
+        self.crosshair_2d.coordinatesClicked2D.connect(
+            lambda x, y: self.clicked_label_2d.setText(f"Clicked Coordinates (2D): x={x}, y={y}")
+        )
+
     def update_table(self, table_widget, x, y_values, column):
         """Update the table with the new coordinates"""
         for i, y in enumerate(y_values):
             table_widget.setItem(i, column, QTableWidgetItem(f"({x}, {y})"))
             table_widget.resizeColumnsToContents()
 
+    def update_curves(self, num_curves):
+        """Update the number of curves"""
+
+        self.plot_item_1d.clear()
+
+        # Curves
+        color_list = ["#384c6b", "#e28a2b", "#5E3023", "#e41a1c", "#984e83", "#4daf4a"]
+        self.plot_item_1d.addLegend()
+        self.curves = []
+
+        y_value_list = self.y_value_list[:num_curves]
+
+        for ii, y_value in enumerate(y_value_list):
+            pen = mkPen(color=color_list[ii], width=2, style=QtCore.Qt.DashLine)
+            curve = pg.PlotDataItem(
+                self.x_data, y_value, pen=pen, skipFiniteCheck=True, name=self.curve_names[ii]
+            )
+            self.plot_item_1d.addItem(curve)
+            self.curves.append(curve)
+
+        self.hook_crosshair()
+
 
 if __name__ == "__main__":
     app = QApplication([])
diff --git a/tests/test_crosshair.py b/tests/test_crosshair.py
new file mode 100644
index 00000000..78a8d8ac
--- /dev/null
+++ b/tests/test_crosshair.py
@@ -0,0 +1,149 @@
+import numpy as np
+import pyqtgraph as pg
+from PyQt5.QtCore import QPointF
+
+from bec_widgets.qt_utils import Crosshair
+
+
+def test_mouse_moved_lines(qtbot):
+    # Create a PlotWidget and add a PlotItem
+    plot_widget = pg.PlotWidget(title="1D PlotWidget with multiple curves")
+    plot_item = plot_widget.getPlotItem()
+    plot_item.plot([1, 2, 3], [4, 5, 6])
+
+    # Create a Crosshair instance
+    crosshair = Crosshair(plot_item=plot_item, precision=2)
+
+    # Connect the signals to slots that will store the emitted values
+    emitted_values_1D = []
+    crosshair.coordinatesChanged1D.connect(emitted_values_1D.append)
+
+    # Simulate a mouse moved event at a specific position
+    pos_in_view = QPointF(2, 5)
+    pos_in_scene = plot_item.vb.mapViewToScene(pos_in_view)
+    event_mock = [pos_in_scene]
+
+    # Call the mouse_moved method
+    crosshair.mouse_moved(event_mock)
+
+    # Assert the expected behavior
+    assert crosshair.v_line.pos().x() == 2
+    assert crosshair.h_line.pos().y() == 5
+
+
+def test_mouse_moved_signals(qtbot):
+    # Create a PlotWidget and add a PlotItem
+    plot_widget = pg.PlotWidget(title="1D PlotWidget with multiple curves")
+    plot_item = plot_widget.getPlotItem()
+    plot_item.plot([1, 2, 3], [4, 5, 6])
+
+    # Create a Crosshair instance
+    crosshair = Crosshair(plot_item=plot_item, precision=2)
+
+    # Create a slot that will store the emitted values as tuples
+    emitted_values_1D = []
+
+    def slot(x, y_values):
+        emitted_values_1D.append((x, y_values))
+
+    # Connect the signal to the custom slot
+    crosshair.coordinatesChanged1D.connect(slot)
+
+    # Simulate a mouse moved event at a specific position
+    pos_in_view = QPointF(2, 5)
+    pos_in_scene = plot_item.vb.mapViewToScene(pos_in_view)
+    event_mock = [pos_in_scene]
+
+    # Call the mouse_moved method
+    crosshair.mouse_moved(event_mock)
+
+    # Assert the expected behavior
+    assert emitted_values_1D == [(2.0, [5.0])]
+
+
+def test_mouse_moved_signals_outside(qtbot):
+    # Create a PlotWidget and add a PlotItem
+    plot_widget = pg.PlotWidget(title="1D PlotWidget with multiple curves")
+    plot_item = plot_widget.getPlotItem()
+    plot_item.plot([1, 2, 3], [4, 5, 6])
+
+    # Create a Crosshair instance
+    crosshair = Crosshair(plot_item=plot_item, precision=2)
+
+    # Create a slot that will store the emitted values as tuples
+    emitted_values_1D = []
+
+    def slot(x, y_values):
+        emitted_values_1D.append((x, y_values))
+
+    # Connect the signal to the custom slot
+    crosshair.coordinatesChanged1D.connect(slot)
+
+    # Simulate a mouse moved event at a specific position
+    pos_in_view = QPointF(22, 55)
+    pos_in_scene = plot_item.vb.mapViewToScene(pos_in_view)
+    event_mock = [pos_in_scene]
+
+    # Call the mouse_moved method
+    crosshair.mouse_moved(event_mock)
+
+    # Assert the expected behavior
+    assert emitted_values_1D == []
+
+
+def test_mouse_moved_signals_2D(qtbot):
+    # write similar test for 2D plot
+
+    # Create a PlotWidget and add a PlotItem
+    plot_widget = pg.PlotWidget(title="2D plot with crosshair and ROI square")
+    data_2D = np.random.random((100, 200))
+    plot_item = plot_widget.getPlotItem()
+    image_item = pg.ImageItem(data_2D)
+    plot_item.addItem(image_item)
+    # Create a Crosshair instance
+    crosshair = Crosshair(plot_item=plot_item)
+    # Create a slot that will store the emitted values as tuples
+    emitted_values_2D = []
+
+    def slot(x, y):
+        emitted_values_2D.append((x, y))
+
+    # Connect the signal to the custom slot
+    crosshair.coordinatesChanged2D.connect(slot)
+    # Simulate a mouse moved event at a specific position
+    pos_in_view = QPointF(22.0, 55.0)
+    pos_in_scene = plot_item.vb.mapViewToScene(pos_in_view)
+    event_mock = [pos_in_scene]
+    # Call the mouse_moved method
+    crosshair.mouse_moved(event_mock)
+    # Assert the expected behavior
+    assert emitted_values_2D == [(22.0, 55.0)]
+
+
+def test_mouse_moved_signals_2D_outside(qtbot):
+    # write similar test for 2D plot
+
+    # Create a PlotWidget and add a PlotItem
+    plot_widget = pg.PlotWidget(title="2D plot with crosshair and ROI square")
+    data_2D = np.random.random((100, 200))
+    plot_item = plot_widget.getPlotItem()
+    image_item = pg.ImageItem(data_2D)
+    plot_item.addItem(image_item)
+    # Create a Crosshair instance
+    crosshair = Crosshair(plot_item=plot_item, precision=2)
+    # Create a slot that will store the emitted values as tuples
+    emitted_values_2D = []
+
+    def slot(x, y):
+        emitted_values_2D.append((x, y))
+
+    # Connect the signal to the custom slot
+    crosshair.coordinatesChanged2D.connect(slot)
+    # Simulate a mouse moved event at a specific position
+    pos_in_view = QPointF(220.0, 555.0)
+    pos_in_scene = plot_item.vb.mapViewToScene(pos_in_view)
+    event_mock = [pos_in_scene]
+    # Call the mouse_moved method
+    crosshair.mouse_moved(event_mock)
+    # Assert the expected behavior
+    assert emitted_values_2D == []