diff --git a/lib/ui/elements/slider_ab.mjs b/lib/ui/elements/slider_ab.mjs
index 01082fad4..b5add9d92 100644
--- a/lib/ui/elements/slider_ab.mjs
+++ b/lib/ui/elements/slider_ab.mjs
@@ -70,28 +70,28 @@ export default function slider_ab(params) {
 
     // Check whether value is a number.
     if (isNaN(value)) return false;
-   
+
     if (params.data_id === 'a' && value > maxInputParams.newValue) {
-  
+
       return false
     }
-  
+
     if (params.data_id === 'b' && value < minInputParams.newValue) {
-  
+
       return false
     }
-  
+
     if (params.min && value < params.min) {
-  
+
       // The value is smaller than min.
       return false
     }
-  
+
     if (params.max) {
-  
+
       return value <= params.max
     }
-  
+
     return true
   }
 
@@ -126,11 +126,11 @@ export default function slider_ab(params) {
         max=${params.max}
         step=${params.step}
         value=${params.val_b}
-        oninput=${onRangeInput}/>`
+        oninput=${e => onRangeInput(e, params)}/>`
 
   // The sliderElement property is required to update the range input on numeric input.
-  minInputParams.sliderElement = element 
-  maxInputParams.sliderElement = element 
+  minInputParams.sliderElement = element
+  maxInputParams.sliderElement = element
 
   /**
   @function onRangeInput
@@ -142,10 +142,11 @@ export default function slider_ab(params) {
 
   @param {Object} e oninput event from range type input.
   */
-  function onRangeInput(e) {
+  function onRangeInput(e, params) {
 
     // Range type input return a string target.value.
     const val = Number(e.target.value)
+    params.onRangeInput = true;
 
     // Check whether input event is from minRangeInput.
     if (e.target.dataset.id === 'a') {