src/vs/workbench/browser/parts/editor/sideBySideEditor.ts/SideBySideEditor/createEditors
class SideBySideEditor:	private createEditors(newInput: SideBySideEditorInput): void {

		// Create editors
		this.secondaryEditorPane = this.doCreateEditor(newInput.secondary, assertIsDefined(this.secondaryEditorContainer));
		this.primaryEditorPane = this.doCreateEditor(newInput.primary, assertIsDefined(this.primaryEditorContainer));

		// Layout
		this.layout(this.dimension);

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

		// Track focus and signal active control change via event
		this.editorDisposables.add(this.primaryEditorPane.onDidFocus(() => this.onDidFocusChange(Side.PRIMARY)));
		this.editorDisposables.add(this.secondaryEditorPane.onDidFocus(() => this.onDidFocusChange(Side.SECONDARY)));
	}