src/vs/workbench/contrib/scm/browser/dirtydiffDecorator.ts/DirtyDiffWorkbenchController/onModelInvisible
class DirtyDiffWorkbenchController:	private onModelInvisible(textFileModel: IResolvedTextFileEditorModel): void {
		this.items.get(textFileModel)!.dispose();
		this.items.delete(textFileModel);
	}