Name the preselected data sources that cannot be used right now

app/MindWork AI Studio/Assistants/I18N/allTexts.lua

@@ -3901,6 +3901,9 @@ UI_TEXT_CONTENT["AISTUDIO::COMPONENTS::DATASOURCESELECTION::T168406579"] = "AI-S
 -- AI-based data validation
 UI_TEXT_CONTENT["AISTUDIO::COMPONENTS::DATASOURCESELECTION::T1744745490"] = "AI-based data validation"
 
+-- 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:
+UI_TEXT_CONTENT["AISTUDIO::COMPONENTS::DATASOURCESELECTION::T1852534051"] = "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:"
+
 -- Yes, I want to use data sources.
 UI_TEXT_CONTENT["AISTUDIO::COMPONENTS::DATASOURCESELECTION::T1975014927"] = "Yes, I want to use data sources."
 
@@ -11587,9 +11590,6 @@ UI_TEXT_CONTENT["AISTUDIO::TOOLS::RAG::DATASOURCESELECTIONPROCESSES::AGENTICSRCS
 -- Automatically selects the appropriate data sources based on the last prompt. Applies a heuristic reduction at the end to reduce the number of data sources.
 UI_TEXT_CONTENT["AISTUDIO::TOOLS::RAG::DATASOURCESELECTIONPROCESSES::AGENTICSRCSELWITHDYNHEUR::T648937779"] = "Automatically selects the appropriate data sources based on the last prompt. Applies a heuristic reduction at the end to reduce the number of data sources."
 
--- None of your selected data sources could be used. This answer was created without them.
-UI_TEXT_CONTENT["AISTUDIO::TOOLS::RAG::RAGPROCESSES::AISRCSELWITHRETCTXVAL::T2995829558"] = "None of your selected data sources could be used. This answer was created without them."
-
 -- This RAG process filters data sources, automatically selects appropriate sources, optionally allows manual source selection, retrieves data, and automatically validates the retrieval context.
 UI_TEXT_CONTENT["AISTUDIO::TOOLS::RAG::RAGPROCESSES::AISRCSELWITHRETCTXVAL::T3047786484"] = "This RAG process filters data sources, automatically selects appropriate sources, optionally allows manual source selection, retrieves data, and automatically validates the retrieval context."
 

app/MindWork AI Studio/Components/DataSourceSelection.razor

@@ -67,6 +67,13 @@
                                 <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:

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

@@ -182,6 +182,22 @@ public partial class DataSourceSelection : MSGComponentBase
         return this.GetConfiguredDataSourcesSnapshot().Where(ds => preselectedDataSourceIds.Contains(ds.Id)).ToList();
     }
 
+    /// <summary>
+    /// Names 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.
+    /// </remarks>
+    /// <returns>The names of the unusable preselected data sources, or an empty string when there are none.</returns>
+    private string GetUnavailablePreselectedDataSourceNames()
+    {
+        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));
+    }
+    
     private async Task LoadAndApplyFilters()
     {
         if(this.DataSourceOptions.DisableDataSources)