src/vs/workbench/browser/parts/editor/sideBySideEditor.ts/SideBySideAwareEditorPaneSelection/compare
class SideBySideAwareEditorPaneSelection:	compare(other: IEditorPaneSelection): EditorPaneSelectionCompareResult {
		if (!(other instanceof SideBySideAwareEditorPaneSelection)) {
			return EditorPaneSelectionCompareResult.DIFFERENT;
		}

		if (this.side !== other.side) {
			return EditorPaneSelectionCompareResult.DIFFERENT;
		}

		return this.selection.compare(other.selection);
	}