diff --git a/modules/Slider.js b/modules/Slider.js
index 198b2d0f8..856c6bed5 100644
--- a/modules/Slider.js
+++ b/modules/Slider.js
@@ -130,10 +130,11 @@ try { // For making it possiblie to run the test app in the following catch stat
               o.v.cbObj = {mode:"incr", value:incr};
             }
           }
-          if (o.v.level!==o.v.prevLevel || o.v.level===0 || o.v.level===o.c.steps) {
-            cb(o.v.cbObj.mode, o.v.cbObj.value); // FIXME: Can cause error when using "incr" since it's not sure that o.v.cbObj has been initialized thanks to how the while-logic above works. (Can also do callback with faulty feedback since it didn't update)
+          if (o.v.cbObj && (o.v.level!==o.v.prevLevel||o.v.level===0||o.v.level===o.c.steps)) {
+            cb(o.v.cbObj.mode, o.v.cbObj.value);
             o.f.draw&&o.f.draw(o.v.level);
           }
+          o.v.cbObj = null;
           o.v.prevLevel = o.v.level;
           o.v.ebLast = e.b;
         }