# HasOpenInstances<T>()

> Checks if an editor window is open.

## Definition

* **Type:** Method
* **Namespace:** [UnityEditor](/engine/6000.3/script-reference/unityeditor.md)
* **Assembly:** UnityEditor

```csharp
public static bool HasOpenInstances<T>() where T : EditorWindow
```

### Returns

| Type                                                          | Description                                                                                                                                                    |
| ------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [bool](https://learn.microsoft.com/dotnet/api/system.boolean) | Returns true if an [EditorWindow](/engine/6000.3/script-reference/unityeditor/editorwindow.md), matching the specified type, is open. Returns false otherwise. |

### Examples

```csharp
using UnityEngine;
using UnityEditor;
using UnityEngine.UIElements;

public class HasOpenInstancesExample : EditorWindow
{
    [MenuItem("Examples/Has Open Instances")]
    static void Init()
    {
        var window = EditorWindow.GetWindow<HasOpenInstancesExample>();
        window.Show();
    }

    [MenuItem("Examples/Close Open Instances")]
    static void Close()
    {
        // Check if any window of type HasOpenInstancesExample is open.
        if (EditorWindow.HasOpenInstances<HasOpenInstancesExample>())
        {
            var window = EditorWindow.GetWindow(typeof(HasOpenInstancesExample));
            window.Close();
        }
    }

    void CreateGUI()
    {
        var label = new Label("Hello, World!");
        rootVisualElement.Add(label);
    }
}
```