Glitch? When I add a comma to my chart updates, two charts show up

So here is my chart data:

#create scatter chart 
event_chart = px.scatter(df, x="mass_1_source", y="mass_2_source", hover_data=["commonName"])


event_chart.update_traces(
    marker=dict(size=10, symbol="circle-dot"),
)
event_chart.update_layout(
   xaxis_title="Mass 1",
    yaxis_title="Mass 2",
),
event_chart.update_xaxes(
    title_font = {"size": 20},
)
event_chart.update_yaxes(
    title_font = {"size": 20},
)

select_event = plotly_events(event_chart, click_event=True)

now when I (accidentally) added a common after the update_layout, another chart appears in my streamline app, this time though it has a black background and it doesn’t let me click on an event, I’m curious on why that is? Is it a glitch and if not, is
there a way for me to keep the chart with the black background instead of the white one? It looks better with the rest of my streamline app. I took a screenshot so you can better see what I mean.