diff --git a/public/script.js b/public/script.js
index 439f6d5..7f407a3 100644
--- a/public/script.js
+++ b/public/script.js
@@ -8,6 +8,7 @@ const fileNames = [];
 let fileType;
 let pendingFiles = 0;
 let formatSelected = false;
+let latestSourcesRequestTarget = null;
 
 dropZone.addEventListener("dragover", (e) => {
   e.preventDefault();
@@ -100,6 +101,7 @@ const showSupportedSources = (targetExtension) => {
       supportedSourcesEl.textContent = `Supported source types: ${unique.join(", ")}`;
     })
     .catch((err) => {
+      if (latestSourcesRequestTarget !== targetExtension) return;
       console.error(err);
       supportedSourcesEl.textContent = "";
     });
diff --git a/src/converters/main.ts b/src/converters/main.ts
index 470471e..9c3650a 100644
--- a/src/converters/main.ts
+++ b/src/converters/main.ts
@@ -299,10 +299,10 @@ for (const converterName in properties) {
     for (const target of toList) {
       const targetClean = normalizeOutputFiletype(target);
 
-      if (!possibleSources[target]) possibleSources[target] = {};
+      if (!possibleSources[targetClean]) possibleSources[targetClean] = {};
  
-      const existing = possibleSources[target][converterName];
-      possibleSources[target][converterName] = existing
+      const existing = possibleSources[targetClean][converterName];
+      possibleSources[targetClean][converterName] = existing
         ? Array.from(new Set([...existing, ...fromList]))
         : [...fromList];
     }