diff --git a/pyzebra/app/panel_ccl_integrate.py b/pyzebra/app/panel_ccl_integrate.py
index 8bfa8fa..179cf72 100644
--- a/pyzebra/app/panel_ccl_integrate.py
+++ b/pyzebra/app/panel_ccl_integrate.py
@@ -254,7 +254,7 @@ def create():
         plot_bkg_source, Line(x="x", y="y", line_color="green", line_dash="dashed")
     )
 
-    plot_peak_source = ColumnDataSource(dict(xs=[0], ys=[0]))
+    plot_peak_source = ColumnDataSource(dict(xs=[[0]], ys=[[0]]))
     plot_peak = plot.add_glyph(
         plot_peak_source, MultiLine(xs="xs", ys="ys", line_color="red", line_dash="dashed")
     )
diff --git a/pyzebra/app/panel_param_study.py b/pyzebra/app/panel_param_study.py
index 0ca473e..4a66277 100644
--- a/pyzebra/app/panel_param_study.py
+++ b/pyzebra/app/panel_param_study.py
@@ -297,7 +297,7 @@ def create():
         plot_bkg_source, Line(x="x", y="y", line_color="green", line_dash="dashed")
     )
 
-    plot_peak_source = ColumnDataSource(dict(xs=[0], ys=[0]))
+    plot_peak_source = ColumnDataSource(dict(xs=[[0]], ys=[[0]]))
     plot_peak = plot.add_glyph(
         plot_peak_source, MultiLine(xs="xs", ys="ys", line_color="red", line_dash="dashed")
     )