My editor window randomly stops working. It works fine at first, but then the window will not appear.

 using UnityEditor;
 using UnityEngine;
 
 public class MyWindow : EditorWindow
 {
     string myString = "Hello World";
     bool groupEnabled;
     bool myBool = true;
     float myFloat = 1.23f;
     
     // Add menu item named "My Window" to the Window menu
     [MenuItem("Window/My Window")]
     public static void ShowWindow()
     {
         //Show existing window instance. If one doesn't exist, make one.
         EditorWindow.GetWindow(typeof(MyWindow));
     }
     
     void OnGUI()
     {
         GUILayout.Label ("Base Settings", EditorStyles.boldLabel);
         myString = EditorGUILayout.TextField ("Text Field", myString);
         
         groupEnabled = EditorGUILayout.BeginToggleGroup ("Optional Settings", groupEnabled);
             myBool = EditorGUILayout.Toggle ("Toggle", myBool);
             myFloat = EditorGUILayout.Slider ("Slider", myFloat, -3, 3);
         EditorGUILayout.EndToggleGroup ();
     }
 }