diff --git a/src/input/MouseZoneManager.ts b/src/input/MouseZoneManager.ts
index ebb91699..8fae3171 100644
--- a/src/input/MouseZoneManager.ts
+++ b/src/input/MouseZoneManager.ts
@@ -170,6 +170,9 @@ export class MouseZoneManager implements IMouseZoneManager {
 
   private _findZoneEventAt(e: MouseEvent): IMouseZone {
     const coords = this._terminal.mouseHelper.getCoords(e, this._terminal.element, this._terminal.charMeasure, this._terminal.options.lineHeight, this._terminal.cols, this._terminal.rows);
+    if (!coords) {
+      return null;
+    }
     for (let i = 0; i < this._zones.length; i++) {
       const zone = this._zones[i];
       if (zone.y === coords[1] && zone.x1 <= coords[0] && zone.x2 > coords[0]) {