diff --git a/simple_analysis/templates/simple_analysis/simple_analysis.html b/simple_analysis/templates/simple_analysis/simple_analysis.html
index 1db8f58..2d0d3f1 100644
--- a/simple_analysis/templates/simple_analysis/simple_analysis.html
+++ b/simple_analysis/templates/simple_analysis/simple_analysis.html
@@ -2594,22 +2594,18 @@ function toggleTrafficPanel() {
 
 function _ensureFlowCanvas() {
     if (!SA.map) return null;
-    const mapEl = SA.map.getContainer();
     let c = document.getElementById(_trafficCanvasId);
     if (!c) {
         c = document.createElement('canvas');
         c.id = _trafficCanvasId;
-        c.style.cssText = 'position:absolute;pointer-events:none;z-index:99999;';
-        // Insert as sibling AFTER map container to stay on top
-        mapEl.parentNode.insertBefore(c, mapEl.nextSibling);
+        c.style.cssText = 'position:fixed;pointer-events:none;z-index:99999;';
+        document.body.appendChild(c);
     }
     const s = SA.map.getSize();
-    const mr = mapEl.getBoundingClientRect();
-    const pr = mapEl.parentNode.getBoundingClientRect();
+    const mr = SA.map.getContainer().getBoundingClientRect();
     c.width = s.x; c.height = s.y;
     c.style.width = s.x + 'px'; c.style.height = s.y + 'px';
-    c.style.left = (mr.left - pr.left) + 'px';
-    c.style.top = (mr.top - pr.top) + 'px';
+    c.style.left = mr.left + 'px'; c.style.top = mr.top + 'px';
     return c;
 }