diff --git a/src/ZenCompactMode.mjs b/src/ZenCompactMode.mjs
index 17d628f..8284d6f 100644
--- a/src/ZenCompactMode.mjs
+++ b/src/ZenCompactMode.mjs
@@ -219,9 +219,9 @@ var gZenCompactModeManager = {
   },
 
   _getCrossedEdge(posX, posY, element = document.documentElement, maxDistance = 10) {
-    posX = Math.max(0, posX);
-    posY = Math.max(0, posY);
     const targetBox = element.getBoundingClientRect();
+    posX = Math.max(0, Math.min(posX, targetBox["right"]));
+    posY = Math.max(0, Math.min(posY, targetBox["bottom"]));
     return ["top", "bottom", "left", "right"].find((edge, i) => {
       const distance = Math.abs((i < 2 ? posY : posX) - targetBox[edge]);
       return distance <= maxDistance;