fix state loss after user switches from steps

app/components/exporter.tsx

@@ -152,10 +152,10 @@ export function MessageExporter() {
         index={currentStepIndex}
         onStepChange={setCurrentStepIndex}
       />
-
-      <div className={styles["message-exporter-body"]}>
-        {currentStep.value === "select" && (
-          <>
+      <div
+        className={styles["message-exporter-body"]}
+        style={currentStep.value !== "select" ? { display: "none" } : {}}
+      >
         <List>
           <ListItem
             title={Locale.Export.Format.Title}
@@ -186,8 +186,7 @@ export function MessageExporter() {
               checked={exportConfig.includeContext}
               onChange={(e) => {
                 updateExportConfig(
-                      (config) =>
-                        (config.includeContext = e.currentTarget.checked),
+                  (config) => (config.includeContext = e.currentTarget.checked),
                 );
               }}
             ></input>
@@ -198,25 +197,19 @@ export function MessageExporter() {
           updateSelection={updateSelection}
           defaultSelectAll
         />
-          </>
-        )}
-
+      </div>
       {currentStep.value === "preview" && (
-          <>
+        <div className={styles["message-exporter-body"]}>
           {exportConfig.format === "text" ? (
             <MarkdownPreviewer
               messages={selectedMessages}
               topic={session.topic}
             />
           ) : (
-              <ImagePreviewer
-                messages={selectedMessages}
-                topic={session.topic}
-              />
-            )}
-          </>
+            <ImagePreviewer messages={selectedMessages} topic={session.topic} />
           )}
         </div>
+      )}
     </>
   );
 }