diff --git a/examples/serve/panels-demo/demo_panels/panel_histo2d.py b/examples/serve/panels-demo/demo_panels/panel_histo2d.py
index c7660c92f..f661144c7 100644
--- a/examples/serve/panels-demo/demo_panels/panel_histo2d.py
+++ b/examples/serve/panels-demo/demo_panels/panel_histo2d.py
@@ -90,6 +90,13 @@ def render_panel(
         },
     )
 
+    progress = CircularProgress(
+        id="plot_progress",
+        hidden=True,
+        size=28,
+        style={"margin": "2px 0"},
+    )
+
     control_bar = Box(
         children=[place_text, controls],
         style={
@@ -127,6 +134,7 @@ def render_panel(
         children=[
             instructions,
             control_bar,
+            progress,
             plot,
             error_message,
         ],
@@ -152,6 +160,7 @@ def render_panel(
     State("@app", "selectedTimeLabel"),
     Input("button", "clicked"),
     Output("plot", "chart"),
+    Output("plot_progress", "hidden"),
 )
 def update_plot(
     ctx: Context,
@@ -161,7 +170,7 @@ def update_plot(
     var_2_name: str | None = None,
     time_label: float | None = None,
     _clicked: bool | None = None,  # trigger, will always be True
-) -> alt.Chart | None:
+) -> tuple[alt.Chart | None, bool]:
     global error_message
     dataset = get_dataset(ctx, dataset_id)
 
@@ -181,12 +190,12 @@ def update_plot(
 
     if place_geometry is None or isinstance(place_geometry, shapely.geometry.Point):
         error_message = "Selected geometry must cover an area."
-        return None
+        return None, True
 
     dataset = mask_dataset_by_geometry(dataset, place_geometry)
     if dataset is None:
         error_message = "Selected geometry produces empty subset"
-        return None
+        return None, True
 
     var_1_data: np.ndarray = dataset[var_1_name].values.ravel()
     var_2_data: np.ndarray = dataset[var_2_name].values.ravel()
@@ -268,7 +277,7 @@ def update_plot(
         height="container",
     )
     error_message = ""
-    return chart
+    return chart, True
 
 
 @panel.callback(
diff --git a/examples/serve/panels-demo/demo_panels/panel_spectrum.py b/examples/serve/panels-demo/demo_panels/panel_spectrum.py
index 1bc8dcf15..0b6a4e10b 100644
--- a/examples/serve/panels-demo/demo_panels/panel_spectrum.py
+++ b/examples/serve/panels-demo/demo_panels/panel_spectrum.py
@@ -17,6 +17,7 @@
 from chartlets import Component, Input, State, Output
 from chartlets.components import (
     Box,
+    CircularProgress,
     Typography,
     VegaChart,
     Radio,
@@ -79,6 +80,13 @@ def render_panel(
         ),
     )
 
+    progress = CircularProgress(
+        id="plot_progress",
+        hidden=True,
+        size=28,
+        style={"margin": "2px 0"},
+    )
+
     control_bar = Box(
         children=[place_text, exploration_radio_group],
         style={
@@ -117,6 +125,7 @@ def render_panel(
         children=[
             instructions,
             control_bar,
+            progress,
             error_message,
             plot,
         ],
@@ -157,10 +166,15 @@ def get_spectra(
     result = pd.DataFrame()
 
     for place in places:
-        i = (dataset_place.name_ref == place).argmax().item()
+        place_index_by_name = {
+            place_name: idx for idx, place_name in enumerate(place_group["name"])
+        }
+
+        place_index = place_index_by_name.get(place)
+
         selected_values = (
             dataset_place.drop_vars("geometry_ref")
-            .sel(idx=i)
+            .sel(idx=place_index)
             .compute()
             .to_dict()["data_vars"]
         )
@@ -214,6 +228,7 @@ def update_text(
     Input("exploration_radio_group", "value"),
     State("plot", "chart"),
     Output("plot", "chart"),
+    Output("plot_progress", "hidden"),
     Output("error_message", "children"),
     Output("@container", "spectrum_list"),
     Output("@container", "previous_mode"),
@@ -228,9 +243,9 @@ def update_plot(
     previous_mode: str | None = None,
     exploration_radio_group: str | None = None,
     current_chart: alt.Chart | None = None,
-) -> tuple[alt.Chart | None, str, list, str]:
+) -> tuple[alt.Chart | None, bool, str, list, str]:
     if exploration_radio_group is None:
-        return None, "Missing exploration mode choice", spectrum_list, previous_mode
+        return None, True, "Missing exploration mode choice", spectrum_list, previous_mode
 
     dataset = get_dataset(ctx, dataset_id)
     has_point = any(
@@ -240,15 +255,16 @@ def update_plot(
     )
 
     if dataset is None:
-        return None, "Missing dataset selection", spectrum_list, exploration_radio_group
+        return None, True, "Missing dataset selection", spectrum_list, exploration_radio_group
     elif not place_group or not has_point:
-        return None, "Missing point selection", spectrum_list, exploration_radio_group
+        return None, True, "Missing point selection", spectrum_list, exploration_radio_group
 
     label = find_selected_point_label(place_group, place_geo)
 
     if label is None:
         return (
             None,
+            True,
             "There is no label for the selected point or no point is selected",
             spectrum_list,
             previous_mode,
@@ -269,14 +285,14 @@ def update_plot(
             ]
         )
     else:
-        return None, "Selected geometry must be a point", spectrum_list, previous_mode
+        return None, True, "Selected geometry must be a point", spectrum_list, previous_mode
 
     place_group_geodf["time"] = pd.to_datetime(time_label).tz_localize(None)
     places_select = [label]
     new_spectrum_data = get_spectra(dataset, place_group_geodf, places_select)
 
     if new_spectrum_data is None or new_spectrum_data.empty:
-        return None, "No reflectances found in Variables", spectrum_list, previous_mode
+        return None, True, "No reflectances found in Variables", spectrum_list, previous_mode
 
     new_spectrum_data["Legend"] = new_spectrum_data["places"] + ": " + time_label
 
@@ -320,7 +336,7 @@ def update_plot(
     )
 
     new_chart = create_chart_from_data(updated_data)
-    return new_chart, "", spectrum_list, exploration_radio_group
+    return new_chart, True, "", spectrum_list, exploration_radio_group
 
 
 def find_selected_point_label(