I can't specify ipywidgets layout attributes of FigureWidget objects, especially grid_area

When I want to specify the grid_area attribute (so that I can place it in a ipywidgets GridBox) I get

Invalid value of type ‘ipywidgets.widgets.widget_layout.Layout’ received for the ‘layout’ property of
Received value: Layout(grid_area=‘bla’)

The 'layout' property is an instance of Layout
that may be specified as:
  - An instance of plotly.graph_objs.Layout
  - A dict of string/value properties that will be passed
    to the Layout constructor

    Supported dict properties:

As a result I can’t place my plotly figure in a GridBox using grid_template_areas. I guess one workaround is to place all my figures in Output widgets but that is a bit tedious. Any suggestions on how to set that attribute?