text: Title: VBox widget not scrollable
  Body: I am trying to build a custom widget class that I want to use for popups in a couple of ipyleaflet Markers. The custom widget consists of a main HBox, which itself contains two VBoxes.. something like this:
  
  ![image](https://github.com/user-attachments/assets/55f1da8c-6616-4304-8fdb-820fa9128ab9)
  
  So far so good.. the smaller VBox on the left is meant to be scrollable. This screenshot was taken from a Jupyter notebook with the ipyleaflet Map as a solara component (see code below). 
  
  However, when I test the same code using solara, the left VBox is not scrollable and its elements are incomplete (e.g., you can't see the "C" item):
  
  ![image](https://github.com/user-attachments/assets/2f0a9781-cff0-458c-a0db-ceaa5f2c1584)
  
  Here's the code:
  
  ```python
  import solara
  import markdown
  import ipyleaflet
  import ipywidgets as widgets
  
  text = """## Test markdown
  
  ### Details
                             
  - **A**: a
  - **B**: b
  - **C**: c
  
  """
  
  class Map(ipyleaflet.Map):
      def __init__(self, **kwargs):
          
          super().__init__(**kwargs)
  
          marker = ipyleaflet.Marker(
              location = (0,0),
              draggable = False,
              title = "My marker",
              popup_max_width=1000,
              popup_max_height=1000
          )
  
          self.add(marker)
  
          main_box = widgets.HBox(
              layout=widgets.Layout(
                  width='1000px',
                  height='480px',
                  justify_content='space-between',
                  )
          )
          panel_box = widgets.VBox(
              layout = widgets.Layout(
                  width='25%',
                  height='100%',
                  border='solid 2px'
              )
          )
          image_box = widgets.VBox(
              layout = widgets.Layout(
                  width='65%',
                  height='100%',
                  border='solid 2px'
              )
          )
  
          value = markdown.markdown(text)
          description_box = widgets.HTML(
              layout=widgets.Layout(
                  border='solid 1px',
                  flex_shrink=1
              ),
              value=value,
          )
  
          panel_box.children = [
              description_box,
              description_box,
              description_box,
              description_box,
          ]
  
          main_box.children=[
              panel_box,
              image_box
          ]
  
  
          marker.popup = main_box
  
  
  @solara.component
  def Page():
      with solara.Column() as main:
          map = Map.element(
              layout=widgets.Layout(height='800px')
          )
      return main
  
  
  display(Page())
  ```
  