diff --git a/corsscripts/stacksortable.js b/corsscripts/stacksortable.js
index 463c5ef2029..a431ccc4d19 100644
--- a/corsscripts/stacksortable.js
+++ b/corsscripts/stacksortable.js
@@ -7,13 +7,21 @@
 
 export const stack_sortable = class {
 
-    constructor(state, inputId, availableId, options = {animation: 50}) {
+    constructor(state, inputId, availableId, options = null) {
         this.state = state;
         this.inputId = inputId;
         this.input = document.getElementById(this.inputId);
         this.availableId = availableId;
         this.available = document.getElementById(this.availableId);
-        this.options = {...{ghostClass: "list-group-item-info", group: "shared"}, ...options};
+        // TODO : additional default options?
+        this.defaultOptions = {animation: 50};
+        if (options == null) {
+            this.userOptions = this.defaultOptions;
+        } else {
+            this.userOptions = Object.assign(this.defaultOptions, options);
+        };
+        // do not allow a user to replace ghostClass or group 
+        this.options = Object.assign(this.userOptions, {ghostClass: "list-group-item-info", group: "shared"});
     }
     
     generate_available(proofSteps) {
diff --git a/corsscripts/stacksortable.min.js b/corsscripts/stacksortable.min.js
index 045e305e854..49dbd593135 100644
--- a/corsscripts/stacksortable.min.js
+++ b/corsscripts/stacksortable.min.js
@@ -1,4 +1,4 @@
 
-export const stack_sortable=class{constructor(state,inputId,availableId,options={animation:50}){this.state=state;this.inputId=inputId;this.input=document.getElementById(this.inputId);this.availableId=availableId;this.available=document.getElementById(this.availableId);this.options={...{ghostClass:"list-group-item-info",group:"shared"},...options};}
+export const stack_sortable=class{constructor(state,inputId,availableId,options=null){this.state=state;this.inputId=inputId;this.input=document.getElementById(this.inputId);this.availableId=availableId;this.available=document.getElementById(this.availableId);this.defaultOptions={animation:50};if(options==null){this.userOptions=this.defaultOptions;}else{this.userOptions=Object.assign(this.defaultOptions,options);};this.options=Object.assign(this.userOptions,{ghostClass:"list-group-item-info",group:"shared"});}
 generate_available(proofSteps){for(const key in this.state.available){let li=document.createElement("li");li.innerText=proofSteps[this.state.available[key]];li.setAttribute("data-id",key);li.className="list-group-item";this.available.append(li);};this.input.value=JSON.stringify(this.state);this.input.dispatchEvent(new Event("change"));}
 update_state(newUsed,newAvailable){var newState={used:[],available:[]};newState.used=newUsed.toArray();newState.available=newAvailable.toArray();this.input.value=JSON.stringify(newState);this.input.dispatchEvent(new Event('change'));this.state=newState;}};export default{stack_sortable};
\ No newline at end of file
diff --git a/doc/en/Topics/Parsons.md b/doc/en/Topics/Parsons.md
index 1ac835b5019..06eca0cefe7 100644
--- a/doc/en/Topics/Parsons.md
+++ b/doc/en/Topics/Parsons.md
@@ -71,7 +71,7 @@ The Parson's drag and drop lists are created using the Sortable JavaScript libra
     "animation": 50,
 }
 ````
-Currently, these cannot be toggled, but shortly one will be able to pass any Sortable option to the lists by having a JSON that is structured as follows in the Parson's block:
+Most Sortable options can be toggled by passing a JSON that is structured as follows in the Parson's block:
 ````
 [[ parsons input="ans1" height="360px" width="100%"]]
 {
@@ -89,11 +89,12 @@ Currently, these cannot be toggled, but shortly one will be able to pass any Sor
 }
 [[/parsons]]
 ````
-
+However, note that some options cannot be toggled as they are required for the proper functioning of the Sortable lists. Hence, any user-defined options for `ghostClass` and `group` are overwritten.
 
 ## Input: ans1
 
-The _Input type_ field should be **String**. The _Model answer_ field should be the Maxima representation of the proof solution. For the above example this should be `proof(1, 2, 3, 4)`.
+The _Input type_ field should be **String**. The _Model answer_ field should be the Maxima representation of the proof solution. 
+For the above example this should be `proof(1, 2, 3, 4)`.
 
 ## Potential response tree: prt1
 
diff --git a/stack/cas/castext2/blocks/parsons.block.php b/stack/cas/castext2/blocks/parsons.block.php
index e7eeb7f1bfe..fc1a3368e95 100644
--- a/stack/cas/castext2/blocks/parsons.block.php
+++ b/stack/cas/castext2/blocks/parsons.block.php
@@ -162,6 +162,13 @@ public function compile($format, $options):  ? MP_Node {
             }
         }
 
+        // parse steps and options separately if they exist
+        $code .= 'var userOpts;' . "\n";
+        $code .= 'if (JSON.stringify(Object.keys(proofSteps)) === JSON.stringify([ "steps", "options" ])) {' . "\n";
+        $code .= 'userOpts = proofSteps["options"];' . "\n";
+        $code .= 'proofSteps = proofSteps["steps"];' . "\n";
+        $code .= '}' . "\n";
+
         // Link up to STACK inputs
         $code .= 'var inputPromise = stack_js.request_access_to_input("' . $this->params['input'] . '", true);' . "\n";
         $code .= 'inputPromise.then((id) => {' . "\n";
@@ -171,7 +178,7 @@ public function compile($format, $options):  ? MP_Node {
         $code .= 'state = {used: [], available: [...Object.keys(proofSteps)]};' . "\n";
 
         // Create the sortable objects by filling in the container div
-        $code .= 'const sortable = new stack_sortable(state, id, "availableList");' . "\n";
+        $code .= 'const sortable = new stack_sortable(state, id, "availableList", userOpts);' . "\n";
         $code .= 'sortable.generate_available(proofSteps);' . "\n";
         $code .= 'MathJax.typesetPromise();' . "\n";
         $code .= 'var opts = {...sortable.options, ...{onSort: () => {sortable.update_state(sortableUsed, sortableAvailable);}}}' . "\n";