Loosing data when changing scene

Hi!

I have a problem with a custom script editor.

There is an string in the script, which I change from the editor. If I hit play, it all works fine, but when I change the scene in the editor and come back to this scene, the string is not saved. Same happens with float sliders.

All the other values (sprites selected, ints, etc.) works fine, so I don't know whats going on.

In the Editor I have:

 showStartImagesScript.nextScene = EditorGUILayout.TextField("Next Scene:", showStartImagesScript.nextScene);

And nextScene is a public string.

I also tried with [SerializeField] but didn't work.

Edit:

Okey, that's what I found now: When I delete the script and Add it again, I can change values, change scene, and it's fine, but I can only do this one time, the next time I change anything, it didn't save.

PD: sry for my english.