Question: I have two subplots sharing x-axis, but it only shows the y-value of one subplot not both. I want the hover-display to show y values from both subplots. Here is what is showing right now:  But I want it to show y values from the bottom chart as well even if I am hovering my mouse on the top chart and vice versa. Here's my code: title = 'Price over time' err = 'Price' fig = make_subplots(rows=2, cols=1, vertical_spacing = 0.05, shared_xaxes=True, subplot_titles=(title,"")) # A fig.add_trace(go.Scatter(x= A_error['CloseDate'], y = A_error[err], line_color = 'green', marker_color = 'green', mode = 'lines+markers', showlegend = True, name = "A", stackgroup = 'one'), row = 1, col = 1, secondary_y = False) # B fig.add_trace(go.Scatter(x= B_error['CloseDate'], y = B_error[err], line_color = 'blue', mode = 'lines+markers', showlegend = True, name = "B", stackgroup = 'one'), row = 2, col = 1, secondary_y = False) fig.update_yaxes(tickprefix = '$') fig.add_hline(y=0, line_width=3, line_dash="dash", line_color="black") fig.update_layout(#height=600, width=1400, hovermode = "x unified", legend_traceorder="normal") 

Answer: Edit: At this time, I don't think a Unified hovermode across the subplots will be provided. I got the rationale for this from here. It does affect some features, but this can be applied to work around it. In your example, the horizontal line does not appear on both graphs. So, I have added two horizontal lines in line mode for scatter plots to accommodate this. With the two stock prices, you have set a threshold value for each. Your objective is the same threshold value, so please modify that. import plotly.express as px import plotly.graph_objects as go from plotly.subplots import make_subplots import yfinance as yf df = yf.download("AAPL MSFT", start="2022-01-01", end="2022-07-01", group_by='ticker') df.reset_index(inplace=True) import plotly.express as px import plotly.graph_objects as go from plotly.subplots import make_subplots title = 'Price over time' err = 'Price' fig = make_subplots(rows=2, cols=1, vertical_spacing = 0.05, shared_xaxes=True, subplot_titles=(title,"")) # AAPL fig.add_trace(go.Scatter(x = df['Date'], y = df[('AAPL', 'Close')], line_color = 'green', marker_color = 'green', mode = 'lines+markers', showlegend = True, name = "AAPL", stackgroup = 'one'), row = 1, col = 1, secondary_y = False) # APPL $150 horizontal line fig.add_trace(go.Scatter(x=df['Date'], y=[125]*len(df['Date']), mode='lines', line_width=3, line_color='black', line_dash='dash', showlegend=False, name='APPL' ), row=1, col=1, secondary_y=False) # MSFT fig.add_trace(go.Scatter(x= df['Date'], y = df[('MSFT', 'Close')], line_color = 'blue', mode = 'lines+markers', showlegend = True, name = "MSFT", stackgroup = 'one'), row = 2, col = 1, secondary_y = False) # MSFT $150 horizontal line fig.add_trace(go.Scatter(x=df['Date'], y=[150]*len(df['Date']), mode='lines', line_width=3, line_color='black', line_dash='dash', showlegend=False, name='MSFT' ), row=2, col=1, secondary_y=False) fig.update_yaxes(tickprefix = '$') fig.update_xaxes(type='date', range=[df['Date'].min(),df['Date'].max()]) #fig.add_hline(y=0, line_width=3, line_dash="dash", line_color="black") fig.update_layout(#height=600, width=1400, hovermode = "x unified", legend_traceorder="normal") fig.update_traces(xaxis='x2') fig.show() enter code here