tui: clear empty-arg slash drafts on dispatch

Co-authored-by: Codex <noreply@openai.com>

codex-rs/tui/src/chatwidget.rs

@@ -4719,6 +4719,8 @@ impl ChatWidget {
             if should_queue && !cmd.requires_interaction() {
                 self.queue_current_inline_bare_slash_command(cmd);
             } else {
+                self.set_composer_text(String::new(), Vec::new(), Vec::new());
+                self.set_remote_image_urls(Vec::new());
                 self.dispatch_command(cmd);
             }
             return;

codex-rs/tui/src/chatwidget/tests.rs

@@ -6055,6 +6055,19 @@ async fn slash_help_opens_reference_popup() {
     assert!(scrolled.contains("/review <instructions>"));
 }
 
+#[tokio::test]
+async fn slash_help_with_whitespace_only_args_clears_composer() {
+    let (mut chat, _rx, _op_rx) = make_chatwidget_manual(None).await;
+
+    chat.bottom_pane
+        .set_composer_text("/help   ".to_string(), Vec::new(), Vec::new());
+    chat.handle_key_event(KeyEvent::new(KeyCode::Enter, KeyModifiers::NONE));
+
+    assert!(chat.bottom_pane.has_active_view());
+    assert_eq!(chat.bottom_pane.composer_text(), "");
+    assert!(chat.remote_image_urls().is_empty());
+}
+
 #[tokio::test]
 async fn slash_help_search_jumps_to_lower_match() {
     let (mut chat, _rx, _op_rx) = make_chatwidget_manual(None).await;