Fix: Resizable Panels via Pointer Events + setPointerCapture

Komplett auf Vanilla JS Pointer Events umgestellt:
- setPointerCapture() fängt ALLE Events am Handle-Element (kein Overlay nötig)
- touch-action: none auf Handles (WebKitGTK Kompatibilität)
- addEventListener in onMount statt Svelte on: Syntax
- Handles als sichtbare 8px Grid-Spalten (nicht absolute)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/routes/+page.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-	import { onMount } from 'svelte';
+	import { onMount, onDestroy } from 'svelte';
 	import SessionList from '$lib/components/SessionList.svelte';
 	import ChatPanel from '$lib/components/ChatPanel.svelte';
 	import ActivityPanel from '$lib/components/ActivityPanel.svelte';
@@ -22,82 +22,20 @@
 		{ id: 'guards', label: 'Guard-Rails', icon: '🛡️' },
 	];
 
-	// ============ Resizable Panels ============
+	// ============ Resizable Panels (Vanilla JS) ============
 
 	let panelWidths = [220, 400, 400, 380];
-	let container: HTMLDivElement;
+	let gridEl: HTMLDivElement;
-	let draggingIdx: number | null = null;
+	let handleEls: HTMLDivElement[] = [];
-	let dragStartX = 0;
-	let dragStartWidths: number[] = [];
 
-	// Panel-Refs für Position-Berechnung
+	function applyWidths() {
-	let panelRefs: HTMLElement[] = [];
+		if (gridEl) {
-
+			gridEl.style.gridTemplateColumns = panelWidths.map(w => `${w}px`).join(' ');
-	function getGridTemplate(): string {
-		return panelWidths.map(w => `${w}px`).join(' ');
-	}
-
-	// Handle-Positionen berechnen (kumulierte Breiten)
-	function getHandlePositions(): number[] {
-		const positions: number[] = [];
-		let cumulative = 0;
-		for (let i = 0; i < panelWidths.length - 1; i++) {
-			cumulative += panelWidths[i];
-			positions.push(cumulative);
 		}
-		return positions;
-	}
-
-	function startDrag(index: number, event: MouseEvent) {
-		event.preventDefault();
-		event.stopPropagation();
-
-		draggingIdx = index;
-		dragStartX = event.clientX;
-		dragStartWidths = [...panelWidths];
-
-		// Text-Selektion sofort blockieren
-		document.body.style.userSelect = 'none';
-		document.body.style.cursor = 'col-resize';
-		window.getSelection()?.removeAllRanges();
-
-		document.addEventListener('mousemove', onDrag);
-		document.addEventListener('mouseup', stopDrag);
-	}
-
-	function onDrag(event: MouseEvent) {
-		if (draggingIdx === null) return;
-		event.preventDefault();
-
-		const dx = event.clientX - dragStartX;
-		const min = 80;
-
-		const li = draggingIdx;
-		const ri = draggingIdx + 1;
-
-		let newL = dragStartWidths[li] + dx;
-		let newR = dragStartWidths[ri] - dx;
-
-		// Clamp
-		if (newL < min) { newR -= (min - newL); newL = min; }
-		if (newR < min) { newL -= (min - newR); newR = min; }
-
-		panelWidths[li] = Math.max(min, newL);
-		panelWidths[ri] = Math.max(min, newR);
-		panelWidths = panelWidths;
-	}
-
-	function stopDrag() {
-		draggingIdx = null;
-		document.body.style.userSelect = '';
-		document.body.style.cursor = '';
-		document.removeEventListener('mousemove', onDrag);
-		document.removeEventListener('mouseup', stopDrag);
-
-		try { localStorage.setItem('panel-widths', JSON.stringify(panelWidths)); } catch {}
 	}
 
 	onMount(() => {
+		// Gespeicherte Breiten laden
 		try {
 			const saved = localStorage.getItem('panel-widths');
 			if (saved) {
@@ -107,31 +45,86 @@
 		} catch {}
 
 		// An Fensterbreite anpassen
-		requestAnimationFrame(() => {
+		if (gridEl) {
-			if (container) {
+			const available = gridEl.parentElement?.clientWidth || window.innerWidth;
-				const available = container.clientWidth;
+			const total = panelWidths.reduce((a, b) => a + b, 0);
-				const total = panelWidths.reduce((a, b) => a + b, 0);
+			if (total > available || total < available * 0.5) {
-				if (total > available || total < available * 0.5) {
+				const scale = available / total;
-					const scale = available / total;
+				panelWidths = panelWidths.map(w => Math.max(80, Math.round(w * scale)));
-					panelWidths = panelWidths.map(w => Math.max(80, Math.round(w * scale)));
-				}
 			}
+		}
+
+		applyWidths();
+
+		// Event-Handler per Vanilla JS an jedes Handle-Element binden
+		handleEls.forEach((el, idx) => {
+			if (!el) return;
+
+			el.addEventListener('pointerdown', (e: PointerEvent) => {
+				e.preventDefault();
+				e.stopPropagation();
+
+				const startX = e.clientX;
+				const startWidths = [...panelWidths];
+				const leftIdx = idx;
+				const rightIdx = idx + 1;
+
+				// Pointer capture — alle Events gehen an dieses Element
+				el.setPointerCapture(e.pointerId);
+				el.classList.add('active');
+
+				document.body.style.userSelect = 'none';
+				document.body.style.cursor = 'col-resize';
+				window.getSelection()?.removeAllRanges();
+
+				function onMove(ev: PointerEvent) {
+					ev.preventDefault();
+					const dx = ev.clientX - startX;
+					const min = 80;
+
+					let newL = startWidths[leftIdx] + dx;
+					let newR = startWidths[rightIdx] - dx;
+
+					if (newL < min) { newR -= (min - newL); newL = min; }
+					if (newR < min) { newL -= (min - newR); newR = min; }
+
+					panelWidths[leftIdx] = Math.max(min, newL);
+					panelWidths[rightIdx] = Math.max(min, newR);
+					applyWidths();
+				}
+
+				function onUp(ev: PointerEvent) {
+					el.releasePointerCapture(ev.pointerId);
+					el.classList.remove('active');
+					document.body.style.userSelect = '';
+					document.body.style.cursor = '';
+
+					el.removeEventListener('pointermove', onMove);
+					el.removeEventListener('pointerup', onUp);
+					el.removeEventListener('pointercancel', onUp);
+
+					try { localStorage.setItem('panel-widths', JSON.stringify(panelWidths)); } catch {}
+				}
+
+				el.addEventListener('pointermove', onMove);
+				el.addEventListener('pointerup', onUp);
+				el.addEventListener('pointercancel', onUp);
+			});
 		});
 	});
-
-	$: handlePositions = getHandlePositions();
 </script>
 
-<div class="layout" bind:this={container}>
+<div class="layout">
-	<!-- Die 4 Panels als einfaches Grid ohne Handle-Spalten -->
+	<div class="grid" bind:this={gridEl}>
-	<div class="panels" style="grid-template-columns: {getGridTemplate()}">
 		<aside class="panel">
 			<SessionList />
 		</aside>
+		<div class="handle" bind:this={handleEls[0]}></div>
 
 		<section class="panel">
 			<ChatPanel />
 		</section>
+		<div class="handle" bind:this={handleEls[1]}></div>
 
 		<section class="panel">
 			<div class="panel-tabs">
@@ -155,6 +148,7 @@
 				{/if}
 			</div>
 		</section>
+		<div class="handle" bind:this={handleEls[2]}></div>
 
 		<section class="panel">
 			<div class="panel-tabs">
@@ -177,35 +171,18 @@
 			</div>
 		</section>
 	</div>
-
-	<!-- Resize-Handles als absolut positionierte Elemente ÜBER den Panels -->
-	{#each handlePositions as pos, i}
-		<!-- svelte-ignore a11y_no_static_element_interactions -->
-		<div
-			class="resize-handle"
-			class:active={draggingIdx === i}
-			style="left: {pos - 4}px"
-			on:mousedown={(e) => startDrag(i, e)}
-		></div>
-	{/each}
-
-	<!-- Drag-Overlay -->
-	{#if draggingIdx !== null}
-		<!-- svelte-ignore a11y_no_static_element_interactions -->
-		<div class="drag-overlay" on:mousemove={onDrag} on:mouseup={stopDrag}></div>
-	{/if}
 </div>
 
 <style>
 	.layout {
-		position: relative;
 		height: 100%;
 		overflow: hidden;
 	}
 
-	.panels {
+	.grid {
 		display: grid;
-		gap: 0;
+		/* 4 Panels + 3 Handles = 7 Spalten, Handles werden via JS positioniert */
+		grid-template-columns: 220px 8px 400px 8px 400px 8px 380px;
 		height: 100%;
 	}
 
@@ -215,37 +192,20 @@
 		background: var(--bg-primary);
 		overflow: hidden;
 		min-width: 0;
-		border-right: 1px solid var(--border);
 	}
 
-	.panel:last-child {
+	/* Handle — eigene Grid-Spalte, Touch-Area */
-		border-right: none;
+	.handle {
-	}
-
-	/* Resize Handle — absolut positioniert, 8px breit, über den Panel-Grenzen */
-	.resize-handle {
-		position: absolute;
-		top: 0;
-		bottom: 0;
 		width: 8px;
 		cursor: col-resize;
-		z-index: 100;
+		background: var(--border);
-		background: transparent;
+		touch-action: none;       /* Wichtig für Pointer Events */
-		transition: background 0.1s ease;
+		user-select: none;
 	}
 
-	.resize-handle:hover,
+	.handle:hover,
-	.resize-handle.active {
+	.handle.active {
 		background: var(--accent);
-		opacity: 0.6;
-	}
-
-	/* Drag-Overlay — fängt ALLE Maus-Events während Drag */
-	.drag-overlay {
-		position: fixed;
-		inset: 0;
-		z-index: 9999;
-		cursor: col-resize;
 	}
 
 	/* Tabs */