How to make Vector3 fields behave like the ones from Transform in a CustomEditor

Question

In the following gif you can see the difference between how Vector3 fields behave in the Inspector of Transform and of my MonoBehaviours.

The Transform is even a CustomEditor I also wrote using EditorGUILayout.Vector3Field().

[CustomEditor(typeof(Transform), true)]
[CanEditMultipleObjects]
public class AdvancedTransformEditor : Editor
{
    //Unity's built-in editor
    private Editor _defaultEditor;
    private Transform _transform;

    private void OnEnable()
    {
        //When this inspector is created, also create the built-in inspector
        _defaultEditor = CreateEditor(targets, Type.GetType("UnityEditor.TransformInspector, UnityEditor"));
        _transform = target as Transform;
    }

    private void OnDisable()
    {
        //When OnDisable is called, the default editor we created should be destroyed to avoid memory leakage.
        //Also, make sure to call any required methods like OnDisable
        var disableMethod = _defaultEditor.GetType().GetMethod("OnDisable", BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);
        if (disableMethod != null) disableMethod.Invoke(_defaultEditor, null);
        DestroyImmediate(_defaultEditor);
    }

    public override void OnInspectorGUI()
    {
        EditorGUILayout.LabelField("Local Space", EditorStyles.boldLabel);
        _defaultEditor.OnInspectorGUI();

        serializedObject.Update();

        //Show World Space Transform
        EditorGUILayout.Space();
        EditorGUILayout.LabelField("World Space", EditorStyles.boldLabel);

        _transform.position = EditorGUILayout.Vector3Field("Position", _transform.position);

        EditorGUI.BeginDisabledGroup(true);
        EditorGUILayout.Vector3Field("Rotation", _transform.eulerAngles);
        EditorGUILayout.Vector3Field("Scale", _transform.lossyScale);
        EditorGUI.EndDisabledGroup();

        serializedObject.ApplyModifiedProperties();
    }
}

It only works while having _defaultEditor.OnInspectorGUI(); so something in Unity's original editor for the Transform component has to do something different.

When I try to do the same in any other CustomEditor for a MonoBehaviour

// without a CustomEditor
public class Example : MonoBehaviour
{
    public Vector3 example;
}

and

// Width the custom editor
public class ExampleMinWidth : MonoBehaviour
{
    public Vector3 example;
}

[CustomEditor(typeof(ExampleMinWidth))]
public class ExampleMinWidthEditor : Editor
{
    private SerializedProperty example;

    private void OnEnable()
    {
        example = serializedObject.FindProperty("exmaple");
    }

    public override void OnInspectorGUI()
    {
        serializedObject.Update();
        example.vector3Value = EditorGUILayout.Vector3Field("Example", example.vector3Value);

        // I tried both also simply using a PropertyField
        //EditorGUILayout.PropertyField(example);
        serializedObject.ApplyModifiedProperties();
    }
}

or skipping the line _defaultEditor.OnInspectorGUI(); in the AdvancedTransformEditor the Vector3 field gets folded for a certain Inspector width.

How can I get the same behaviour for my fields as for the Transform component - not folding but staying on the same line?

---

Update

• I tried it with GUILayout.MinWidth() but this didn't change anything.

• As suggested I also tried

  example.vector3Value = EditorGUILayout.Vector3Field("Example", example.vector3Value, GUILayout.ExpandHeight(false));
  

  (also for the PropertyField()) but that didn't change anything.

• And Just for trying I also did with ExpandWidth(false) ... the outcome is not very pleasing :D

  

• I even tried GUILayout.MaxHeight(EditorGUIUtility.singleLineHeight) but that makes the field still fold but "bload"/overdraw into the field below.

Answer 1

I found the relevant lines in the TransformInspector

if (!EditorGUIUtility.wideMode)
{
    EditorGUIUtility.wideMode = true;
    EditorGUIUtility.labelWidth = EditorGUIUtility.currentViewWidth - 212;
}

• EditorGUIUtility.wideMode does two things: Returns whether the editor currently is in widemode and set whether the editor for this component / the next lines shall be behaving like it was in widemode. So they simply force their fields to only "be" in widemode.

• After that it is necessary to use a "fixed" EditorGUIUtility.labelWidth namely reduced by the width the 3 Vectror3 fields will take in widemode (Unity used 212)