Missed a default

Author: cpsievert

shiny/ui/_markdown_stream.py

@@ -265,13 +265,14 @@ async def _raise_exception(self, e: BaseException):
 
 @add_example("app-express.py")
 class ExpressMarkdownStream(MarkdownStream):
+
     def ui(
         self,
         *,
         content: TagChild = "",
         content_type: StreamingContentType = "markdown",
         auto_scroll: bool = True,
-        width: CssUnit = "100%",
+        width: CssUnit = "min(680px, 100%)",
         height: CssUnit = "auto",
     ) -> Tag:
         """