Unable to preserve current model of modified DiffEditor

Describe the bug We have a use-case, similar to Azure DevOps above, where we allow the user to flip between the normal Editor and the DiffEditor.

This mostly works great except that when switching from the DiffEditor to the Editor, we are unable to use the DiffEditor’s modified model as the model of the Editor. In the flip scenario, switching from the Editor to the DiffEditor, we can do this because of the keepCurrentModel prop allowed on the Editor, but it seems that the DiffEditor is lacking this ability.

We could benefit from one of two things:

1. Advice/Examples on how to implement this pattern.
2. A keepCurrentModifiedModel prop (or something similar) for the DiffEditor that allows the consumer to prevent the modified model from being disposed on unmount.

To Reproduce Our setup is similar to below. We keep a ref for the current model and set that ref in the onMount function of each editor.

const isDiff = React.useState(false);
const model = React.useRef<monaco.editor.ITextModel>();
return {isDiff ? 
   <DiffEditor
      onMount={diffEditor => 
         model.current && diffEditor.setModel({ original: diffEditor.getModel().original, modified: model.current });
         model.current = diffEditor.getModel().modified;
   /> : 
   <Editor 
       keepCurrentModel
       onMount={editor => 
       // model.current && editor.setModel(model.current); <--- ERROR because at this point the DiffEditor's model is disposed!
        model.current = editor.getModel();
  />;

[suren-atoyan]

@dehoward done

check the version - v4.1.3

Thank you for your support!

[dehoward]

https://github.com/suren-atoyan/monaco-react/pull/235