src/vs/workbench/browser/parts/editor/sideBySideEditor.ts/SideBySideEditor/createEditor
class SideBySideEditor:	protected createEditor(parent: HTMLElement): void {
		parent.classList.add('side-by-side-editor');

		// Editor pane containers
		this.secondaryEditorContainer = $('.side-by-side-editor-container.editor-instance');
		this.primaryEditorContainer = $('.side-by-side-editor-container.editor-instance');

		// Split view
		this.createSplitView(parent);
	}