src/vs/workbench/browser/parts/editor/textDiffEditor.ts/TextDiffEditor/onWillCloseEditorInGroup
class TextDiffEditor:	protected override onWillCloseEditorInGroup(editor: IEditorInput): void {

		// React to editors closing to preserve or clear view state. This needs to happen
		// in the onWillCloseEditor because at that time the editor has not yet
		// been disposed and we can safely persist the view state still as needed.
		this.doSaveOrClearTextDiffEditorViewState(editor);
	}