List the preselected data sources that cannot be used right now

app/MindWork AI Studio/Components/DataSourceSelection.razor

@@ -67,13 +67,6 @@
                                 <MudTextSwitch Label="@T("AI-based data validation")" Value="@this.aiBasedValidation" LabelOn="@T("Yes, let the AI validate & filter the retrieved data.")" LabelOff="@T("No, use all data retrieved from the data sources.")" ValueChanged="@this.ValidationModeChanged"/>
                             }
 
-                            @if (!this.aiBasedSourceSelection && this.GetUnavailablePreselectedDataSourceNames().Length > 0)
-                            {
-                                <MudText Typo="Typo.body2" Color="Color.Warning" Class="mb-3">
-                                    @T("These data sources are preselected, but cannot be used right now, either due to data privacy or confidence-level requirements, or because they are unavailable:") @this.GetUnavailablePreselectedDataSourceNames()
-                                </MudText>
-                            }
-
                             @switch (this.aiBasedSourceSelection)
                             {
                                 case true when this.availableDataSources.Count == 0:
@@ -172,11 +165,24 @@
                                     </MudExpansionPanels>
                                     break;
                             }
+
+                            @if (!this.aiBasedSourceSelection && this.GetUnavailablePreselectedDataSources().Count > 0)
+                            {
+                                <MudJustifiedText Typo="Typo.body2" Color="Color.Warning">
+                                    @T("These data sources are preselected, but cannot be used right now, either due to data privacy or confidence-level requirements, or because they are unavailable:")
+                                </MudJustifiedText>
+                                <ul class="unavailable-data-sources mb-3 mt-1">
+                                    @foreach (var source in this.GetUnavailablePreselectedDataSources())
+                                    {
+                                        <li>@source.Name</li>
+                                    }
+                                </ul>
+                            }
                         }
                     }
                 </MudCardContent>
                 <MudCardActions>
-                    <MudButton Variant="Variant.Filled" OnClick="@(() => this.HideDataSourceSelection())">
+                    <MudButton Variant="Variant.Filled" OnClick="@this.HideDataSourceSelection">
                         @T("Close")
                     </MudButton>
                 </MudCardActions>

app/MindWork AI Studio/Components/DataSourceSelection.razor.cs

@@ -183,19 +183,19 @@ public partial class DataSourceSelection : MSGComponentBase
     }
 
     /// <summary>
-    /// Names the preselected data sources which the filters removed.
+    /// Collects the preselected data sources which the filters removed.
     /// </summary>
     /// <remarks>
-    /// This list shows what survived the filters, while the preselection keeps what the user asked
-    /// for. Without this, a preselected source which cannot be used right now is simply missing
-    /// from the list, and nothing says so. Preselected ids without a configured source are left
-    /// out: that source is gone, not unavailable.
+    /// The list of available sources shows what survived the filters, while the preselection keeps
+    /// what the user asked for. Without this, a preselected source which cannot be used right now
+    /// is simply missing from that list, and nothing says so. Preselected ids without a configured
+    /// source are left out: that source is gone, not unavailable.
     /// </remarks>
-    /// <returns>The names of the unusable preselected data sources, or an empty string when there are none.</returns>
-    private string GetUnavailablePreselectedDataSourceNames()
+    /// <returns>The unusable preselected data sources, or an empty list when there are none.</returns>
+    private IReadOnlyList<IDataSource> GetUnavailablePreselectedDataSources()
     {
         var availableDataSourceIds = this.availableDataSources.Select(ds => ds.Id).ToHashSet(StringComparer.Ordinal);
-        return string.Join(", ", this.GetDataSourcesFromConfiguredIds().Where(ds => !availableDataSourceIds.Contains(ds.Id)).Select(ds => ds.Name));
+        return this.GetDataSourcesFromConfiguredIds().Where(ds => !availableDataSourceIds.Contains(ds.Id)).ToList();
     }
     
     private async Task LoadAndApplyFilters()

app/MindWork AI Studio/Components/DataSourceSelection.razor.css

@@ -0,0 +1,18 @@
+/*
+ * A plain list renders without markers and without indentation here: something in the global
+ * styles takes both off. This is an enumeration of names and wants to read as one, so it states
+ * marker, indentation and spacing itself. MudBlazor's Markdown styles fight the same fight for
+ * their own lists, and need an !important on the display to win it -- hence the one below.
+ */
+.unavailable-data-sources {
+    max-height: 10em;
+    overflow-y: auto;
+    overflow-wrap: anywhere;
+    margin-top: 0;
+    padding-left: 1.5em;
+    list-style: disc outside;
+}
+
+.unavailable-data-sources li {
+    display: list-item !important;
+}