diff --git a/tk_annotation_gui.py b/tk_annotation_gui.py
index f9227067..f59331bb 100644
--- a/tk_annotation_gui.py
+++ b/tk_annotation_gui.py
@@ -673,6 +673,37 @@ class TkAnnotationApp:
         self.drag_start = (event_x, event_y)
         self._redraw_boxes()
 
+    def _apply_move_drag(self, event_x: float, event_y: float) -> None:
+        if (
+            not self.dragging
+            or self.drag_mode != "move"
+            or self.selected_box_index is None
+            or self.drag_start is None
+            or self.current_image_path is None
+        ):
+            return
+
+        boxes = self.annotations.get(self.current_image_path.name, []) or []
+        if self.selected_box_index >= len(boxes):
+            return
+
+        bbox = boxes[self.selected_box_index]["bbox"]
+        x1, y1, x2, y2 = bbox
+        # Convert to display coords, move, convert back
+        dx1, dy1 = self._img_to_disp(x1, y1)
+        dx2, dy2 = self._img_to_disp(x2, y2)
+        dx = event_x - self.drag_start[0]
+        dy = event_y - self.drag_start[1]
+        dx1 += dx
+        dy1 += dy
+        dx2 += dx
+        dy2 += dy
+        ix1, iy1 = self._disp_to_img(dx1, dy1)
+        ix2, iy2 = self._disp_to_img(dx2, dy2)
+        boxes[self.selected_box_index]["bbox"] = [ix1, iy1, ix2, iy2]
+        self.drag_start = (event_x, event_y)
+        self._redraw_boxes()
+
     # ------------------------- Mouse interactions -------------------------
 
     def _on_mouse_down(self, event: tk.Event) -> None:
@@ -700,18 +731,6 @@ class TkAnnotationApp:
         
         # Check if Ctrl is held for moving or resizing boxes
         if event.state & 0x4:  # Ctrl key
-            # First, check if clicking on a corner of the selected box for resizing
-            if self.selected_box_index is not None:
-                corner = self._find_resize_corner(event.x, event.y, self.selected_box_index)
-                if corner:
-                    self.dragging = True
-                    self.drag_mode = 'resize'
-                    self.resize_corner = corner
-                    self.drag_start = (event.x, event.y)
-                    self._refresh_box_list()
-                    self._redraw_boxes()
-                    return
-            
             # Otherwise, select and move a box
             if box_index is not None:
                 self.selected_box_index = box_index
@@ -722,12 +741,20 @@ class TkAnnotationApp:
                 self._redraw_boxes()
                 return
 
-        # Normal mode: check if clicking inside a box to potentially select it
+        # Normal mode: check if clicking inside a box
         if box_index is not None:
-            self._potential_select = box_index
-            self._is_selecting = True
-            self._mouse_moved = False
-            return
+            if box_index == self.selected_box_index:
+                # If clicking on the already selected box, start moving it
+                self.dragging = True
+                self.drag_mode = 'move'
+                self.drag_start = (event.x, event.y)
+                return
+            else:
+                # Otherwise, potentially select it
+                self._potential_select = box_index
+                self._is_selecting = True
+                self._mouse_moved = False
+                return
         
         # Otherwise, start drawing
         self._draw_start = (event.x, event.y)
@@ -741,34 +768,8 @@ class TkAnnotationApp:
             self._apply_resize_drag(event.x, event.y)
             return
 
-        if self.dragging and self.drag_mode == 'move' and self.drag_start and self.selected_box_index is not None:
-            # Move the box
-            dx = event.x - self.drag_start[0]
-            dy = event.y - self.drag_start[1]
-            if self.current_image_path is None:
-                return
-            boxes = self.annotations.get(self.current_image_path.name, []) or []
-            if self.selected_box_index >= len(boxes):
-                return
-            bbox = boxes[self.selected_box_index]["bbox"]
-            x1, y1, x2, y2 = bbox
-            # Convert to display coords, move, convert back
-            dx1, dy1 = self._img_to_disp(x1, y1)
-            dx2, dy2 = self._img_to_disp(x2, y2)
-            dx1 += dx
-            dy1 += dy
-            dx2 += dx
-            dy2 += dy
-            ix1, iy1 = self._disp_to_img(dx1, dy1)
-            ix2, iy2 = self._disp_to_img(dx2, dy2)
-            boxes[self.selected_box_index]["bbox"] = [ix1, iy1, ix2, iy2]
-            self.drag_start = (event.x, event.y)
-            self._redraw_boxes()
-            return
-        
-        if self._is_selecting:
-            self._mouse_moved = True
-            return
+        if self.dragging and self.drag_mode == "move":
+            self._apply_move_drag(event.x, event.y)
         
         if self._draw_start is None or self.current_image is None or self.transform is None:
             return