diff --git a/src/components/ThreeScene.tsx b/src/components/ThreeScene.tsx
index cf53102..9adef07 100644
--- a/src/components/ThreeScene.tsx
+++ b/src/components/ThreeScene.tsx
@@ -51,6 +51,7 @@ const [labelPositions, setLabelPositions] = useState<
 		const defaultLineOpacity = 0.1;
 		let outlineMesh: THREE.Mesh | null = null;
 		let previouslyHoveredSphere: THREE.Mesh | null = null;
+		let highlightedLines: THREE.Line[] = [];
 
 		type OverlayInfo = { overlay: HTMLDivElement, node: THREE.Object3D };
 		let neighborOverlays: OverlayInfo[] = [];
@@ -166,6 +167,7 @@ const [labelPositions, setLabelPositions] = useState<
 		const sphereGroup = new THREE.Group();
 		const lineGroup = new THREE.Group();
 		const nodeMap: { [key: string]: THREE.Vector3 } = {};
+		const sphereByLabel = new Map<string, THREE.Object3D>();
 
 		data.nodes.forEach((node) => {
 			//const material = new THREE.MeshNormalMaterial();
@@ -192,6 +194,7 @@ const [labelPositions, setLabelPositions] = useState<
 			sphere.userData.displayUrl = `https://scrapbox.io/${projectName}/${node.text}`;
 			sphere.userData.label = node.text;
 			sphereGroup.add(sphere);
+			sphereByLabel.set(node.text, sphere);
 /*
 			sphereGroup.add(sphere);
 
@@ -218,10 +221,10 @@ const [labelPositions, setLabelPositions] = useState<
 					opacity: defaultLineOpacity
 					});
 				const line = new THREE.Line(lineGeometry, lineMaterial);
-				lineGroup.add(line)
+				lineGroup.add(line);
 
-				const sourceSphere = sphereGroup.children.find(o => o.userData.displayUrl?.endsWith(link.source));
-				const targetSphere = sphereGroup.children.find(o => o.userData.displayUrl?.endsWith(link.target));
+				const sourceSphere = sphereByLabel.get(link.source);
+				const targetSphere = sphereByLabel.get(link.target);
 				if (sourceSphere && targetSphere) {
 					const sourceWorldPos = new THREE.Vector3();
 					sourceSphere.getWorldPosition(sourceWorldPos);
@@ -331,11 +334,13 @@ const [labelPositions, setLabelPositions] = useState<
 			);
 			const urlDisplay =  urlDisplayRef.current;
 
-			lineGroup.children.forEach(line => {
-				if ((line as THREE.Line).material instanceof THREE.LineBasicMaterial) {
-					((line as THREE.Line).material as THREE.LineBasicMaterial).opacity = defaultLineOpacity;
+			// Reset only previously highlighted lines instead of all lines
+			highlightedLines.forEach(line => {
+				if (line.material instanceof THREE.LineBasicMaterial) {
+					(line.material as THREE.LineBasicMaterial).opacity = defaultLineOpacity;
 				}
 			});
+			highlightedLines = [];
 
 			if (outlineMesh) {
 				scene.remove(outlineMesh);
@@ -426,6 +431,7 @@ const [labelPositions, setLabelPositions] = useState<
 					lines.forEach((line) => {
 						const mat = line.material as THREE.LineBasicMaterial;
 						mat.opacity = 1.0;
+						highlightedLines.push(line);
 					});
 				}
 			}