src/vs/workbench/browser/parts/editor/sideBySideEditor.ts/SideBySideEditor/setNewInput
class SideBySideEditor:	private async setNewInput(newInput: SideBySideEditorInput, options: IEditorOptions | undefined, context: IEditorOpenContext, token: CancellationToken): Promise<void> {
		this.secondaryEditorPane = this.doCreateEditor(newInput.secondary, assertIsDefined(this.secondaryEditorContainer));
		this.primaryEditorPane = this.doCreateEditor(newInput.primary, assertIsDefined(this.primaryEditorContainer));

		this.layout(this.dimension);

		this._onDidChangeSizeConstraints.input = Event.any(
			Event.map(this.secondaryEditorPane.onDidChangeSizeConstraints, () => undefined),
			Event.map(this.primaryEditorPane.onDidChangeSizeConstraints, () => undefined)
		);

		this.onDidCreateEditors.fire(undefined);

		await Promise.all([
			this.secondaryEditorPane.setInput(newInput.secondary, undefined, context, token),
			this.primaryEditorPane.setInput(newInput.primary, options, context, token)]
		);
	}