Merge pull request #66 from wtachau/patch-1

fix: dynamic loading of content when splitpanes are rendered in a separate part of the DOM tree

src/lib/Splitpanes.svelte

@@ -929,6 +929,9 @@
 		and if not update the internal order.
 	 */
 	function verifyAndUpdatePanesOrder() {
+		if (!container) {
+			return;
+		}
 		const { children } = container;
 		let currentPaneIndex = 0;
 		let needReorder = false;