diff --git a/html_resources/selector.js b/html_resources/selector.js
index e6b4e89..b963257 100644
--- a/html_resources/selector.js
+++ b/html_resources/selector.js
@@ -104,8 +104,18 @@ function getSecondaryCategories(list){
   return ret
 }
 
+function clearCodeBlock(){
+  const pre = document.getElementById("previewBox");
+  for(let el of Array.from(pre.childNodes)){
+    pre.remove(el)
+  }
+  return
+}
+
 async function onCategoryClicked(categoryNode,isSecondary = false){
   
+  clearCodeBlock();
+  
   currentCategory.set(categoryNode,isSecondary);
   // Using textContent is bad but meh
   //let names = DB.query(categoryNode.textContent);