Fix use prefixLabel position right away

Author: JohannesDeml

Assets/MackySoft/MackySoft.SerializeReferenceExtensions/Editor/SubclassSelectorDrawer.cs

@@ -35,19 +35,14 @@ public override void OnGUI (Rect position,SerializedProperty property,GUIContent
 			EditorGUI.BeginProperty(position,label,property);
 
 			if (property.propertyType == SerializedPropertyType.ManagedReference) {
-				
+
 				// render label first to avoid label overlap for lists
 				Rect foldoutLabelRect = new Rect(position);
 				foldoutLabelRect.height = EditorGUIUtility.singleLineHeight;
 				foldoutLabelRect.x += EditorGUI.indentLevel * 12;
-				EditorGUI.PrefixLabel(foldoutLabelRect, label);
-				
-				// Draw the subclass selector popup.
-				Rect popupPosition = new Rect(position);
-				popupPosition.width -= EditorGUIUtility.labelWidth;
-				popupPosition.x += EditorGUIUtility.labelWidth;
-				popupPosition.height = EditorGUIUtility.singleLineHeight;
+				Rect popupPosition = EditorGUI.PrefixLabel(foldoutLabelRect, label);
 
+				// Draw the subclass selector popup.
 				if (EditorGUI.DropdownButton(popupPosition,GetTypeName(property),FocusType.Keyboard)) {
 					TypePopupCache popup = GetTypePopup(property);
 					m_TargetProperty = property;
@@ -62,7 +57,7 @@ public override void OnGUI (Rect position,SerializedProperty property,GUIContent
 					Rect foldoutRect = new Rect(position);
 					foldoutRect.height = EditorGUIUtility.singleLineHeight;
 					property.isExpanded = EditorGUI.Foldout(foldoutRect, property.isExpanded, GUIContent.none, true);
-					
+
 					if (property.isExpanded)
 					{
 						using (new EditorGUI.IndentLevelScope())
@@ -102,7 +97,7 @@ TypePopupCache GetTypePopup (SerializedProperty property) {
 
 			if (!m_TypePopups.TryGetValue(managedReferenceFieldTypename,out TypePopupCache result)) {
 				var state = new AdvancedDropdownState();
-				
+
 				Type baseType = ManagedReferenceUtility.GetType(managedReferenceFieldTypename);
 				var popup = new AdvancedTypePopup(
 					TypeCache.GetTypesDerivedFrom(baseType).Append(baseType).Where(p =>
@@ -125,7 +120,7 @@ TypePopupCache GetTypePopup (SerializedProperty property) {
 
 						object obj = individualProperty.SetManagedReference(type);
 						individualProperty.isExpanded = (obj != null);
-						
+
 						individualObject.ApplyModifiedProperties();
 						individualObject.Update();
 					}