diff --git a/frontend/js/labs/organic.js b/frontend/js/labs/organic.js
index 498d79b..dc23237 100644
--- a/frontend/js/labs/organic.js
+++ b/frontend/js/labs/organic.js
@@ -1252,10 +1252,16 @@ class OrganicSim {
     center.style.cssText = 'flex:1;display:flex;flex-direction:column;overflow:hidden;position:relative';
     panel.appendChild(center);
 
+    // wrapper makes the canvas position:absolute so its intrinsic pixel size
+    // (set in _drawQual) can't feed back into the flex layout and inflate height
+    const canvasWrap = document.createElement('div');
+    canvasWrap.style.cssText = 'flex:1;position:relative;overflow:hidden';
+    center.appendChild(canvasWrap);
+
     const qualCanvas = document.createElement('canvas');
-    qualCanvas.style.cssText = 'width:100%;flex:1;display:block';
+    qualCanvas.style.cssText = 'position:absolute;top:0;left:0;width:100%;height:100%';
     this._qualCanvas = qualCanvas;
-    center.appendChild(qualCanvas);
+    canvasWrap.appendChild(qualCanvas);
 
     // compounds area
     const compArea = document.createElement('div');