diff --git a/projects/GKCore/GDModel/GDMList.cs b/projects/GKCore/GDModel/GDMList.cs
index 46bd4e358..4fea4c65a 100644
--- a/projects/GKCore/GDModel/GDMList.cs
+++ b/projects/GKCore/GDModel/GDMList.cs
@@ -95,7 +95,7 @@ public int Count
         public T this[int index]
         {
             get {
-                return (fDataList == null) ? default(T) : fDataList[index];
+                return (fDataList == null) ? default : fDataList[index];
             }
         }
         
@@ -204,7 +204,7 @@ public void Exchange(int index1, int index2)
 
         public T Extract(int index)
         {
-            if (fDataList == null) return default(T);
+            if (fDataList == null) return default;
 
             T result = fDataList[index];
             fDataList.RemoveAt(index);
@@ -213,14 +213,14 @@ public T Extract(int index)
 
         public T Extract(T item)
         {
-            if (fDataList == null) return default(T);
+            if (fDataList == null) return default;
 
             int index = fDataList.IndexOf(item);
             if (index >= 0) {
                 fDataList.RemoveAt(index);
                 return item;
             } else {
-                return default(T);
+                return default;
             }
         }
 
diff --git a/projects/GKCore/GDModel/GDMLocationRecord.cs b/projects/GKCore/GDModel/GDMLocationRecord.cs
index 84bc738f8..340c1a244 100644
--- a/projects/GKCore/GDModel/GDMLocationRecord.cs
+++ b/projects/GKCore/GDModel/GDMLocationRecord.cs
@@ -242,7 +242,7 @@ public GDMList<GDMLocationName> GetFullNames(GDMTree tree, ATDEnumeration atdEnu
                         }
                     }
 
-                    if (topBuffer.Count == 0 || !locDate.IsEmpty()) {
+                    if (topBuffer.Count == 0 || (locDate != null && !locDate.IsEmpty())) {
                         result.Add(new GDMLocationName(nVal, locDate));
                     }
                 }
diff --git a/projects/GKCore/GKCore/GKData.cs b/projects/GKCore/GKCore/GKData.cs
index 3507eb0ed..1a2146fc2 100644
--- a/projects/GKCore/GKCore/GKData.cs
+++ b/projects/GKCore/GKCore/GKData.cs
@@ -390,12 +390,12 @@ static GKData()
                 new PredefinedEvent(LSID.PersonalProperty, GEDCOMTagName.PROP, EventKind.ekFact, EventTarget.etIndividual),
                 new PredefinedEvent(LSID.NobilityTitle, GEDCOMTagName.TITL, EventKind.ekFact, EventTarget.etIndividual),
 
-                new PredefinedEvent(LSID.Travel, GEDCOMTagName._TRAVEL, EventKind.ekFact, EventTarget.etIndividual),
+                new PredefinedEvent(LSID.Travel, GEDCOMTagName._TRAVEL, EventKind.ekFact, EventTarget.etIndividual, true),
                 new PredefinedEvent(LSID.Hobby, GEDCOMTagName._HOBBY, EventKind.ekFact, EventTarget.etIndividual),
                 new PredefinedEvent(LSID.Award, GEDCOMTagName._AWARD, EventKind.ekFact, EventTarget.etIndividual),
                 new PredefinedEvent(LSID.Mili, GEDCOMTagName._MILI, EventKind.ekFact, EventTarget.etIndividual),
-                new PredefinedEvent(LSID.MiliInd, GEDCOMTagName._MILI_IND, EventKind.ekFact, EventTarget.etIndividual),
-                new PredefinedEvent(LSID.MiliDis, GEDCOMTagName._MILI_DIS, EventKind.ekFact, EventTarget.etIndividual),
+                new PredefinedEvent(LSID.MiliInd, GEDCOMTagName._MILI_IND, EventKind.ekFact, EventTarget.etIndividual, true),
+                new PredefinedEvent(LSID.MiliDis, GEDCOMTagName._MILI_DIS, EventKind.ekFact, EventTarget.etIndividual, true),
                 new PredefinedEvent(LSID.MiliRank, GEDCOMTagName._MILI_RANK, EventKind.ekFact, EventTarget.etIndividual),
 
                 new PredefinedEvent(LSID.BloodGroup, GEDCOMTagName._BGRO, EventKind.ekFact, EventTarget.etIndividual),
diff --git a/projects/GKCore/GKCore/Lists/ListSource.cs b/projects/GKCore/GKCore/Lists/ListSource.cs
index dcbabdc6e..d9a89c1d2 100644
--- a/projects/GKCore/GKCore/Lists/ListSource.cs
+++ b/projects/GKCore/GKCore/Lists/ListSource.cs
@@ -137,7 +137,7 @@ public void Clear()
             fExternalFilter = null;
             fFilter.Clear();
 
-            fFetchedRec = default(T);
+            fFetchedRec = default;
 
             fColumnsMap.Clear();
             fListColumns.Clear();
diff --git a/projects/GKCore/GKCore/NetDiff/DiffUtil.cs b/projects/GKCore/GKCore/NetDiff/DiffUtil.cs
index 784204e25..50c070647 100644
--- a/projects/GKCore/GKCore/NetDiff/DiffUtil.cs
+++ b/projects/GKCore/GKCore/NetDiff/DiffUtil.cs
@@ -132,8 +132,8 @@ private static IEnumerable<DiffResult<T>> MakeResults<T>(IEnumerable<Point> wayp
             foreach (var pair in MakePairsWithNext(waypoints))
             {
                 var status = GetStatus(pair.Item1, pair.Item2);
-                T obj1 = default(T);
-                T obj2 = default(T);
+                T obj1 = default;
+                T obj2 = default;
                 switch (status)
                 {
                     case DiffStatus.Equal:
@@ -276,8 +276,7 @@ internal class EditGraph<T>
             private int offset;
             private bool isEnd;
 
-            public EditGraph(
-                IEnumerable<T> seq1, IEnumerable<T> seq2)
+            public EditGraph(IEnumerable<T> seq1, IEnumerable<T> seq2)
             {
                 this.seq1 = seq1.ToArray();
                 this.seq2 = seq2.ToArray();
diff --git a/projects/GKCore/GKCore/ScriptEngine.cs b/projects/GKCore/GKCore/ScriptEngine.cs
index 91f0cbe63..6a8072273 100644
--- a/projects/GKCore/GKCore/ScriptEngine.cs
+++ b/projects/GKCore/GKCore/ScriptEngine.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,13 +18,15 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#pragma warning disable IDE0060 // Remove unused parameter
+#pragma warning disable IDE1006 // Naming Styles
+
 #if !MOBILE
 
 using System;
 using System.Data;
 using System.IO;
 using System.Reflection;
-using System.Text;
 using BSLib;
 using GDModel;
 using GDModel.Providers.GEDCOM;
@@ -54,7 +56,7 @@ public ScriptException(string message) : base(message)
     public class ScriptEngine
     {
         private IBaseWindow fBase;
-        private IScriptConsole fView;
+        private readonly IScriptConsole fView;
 
         public ScriptEngine(IScriptConsole view)
         {
@@ -92,15 +94,15 @@ private void lua_register(Lua lvm, string funcName)
 
         private void lua_init(Lua lvm)
         {
-            lua_register(lvm, "print");
-            lua_register(lvm, "progress_init");
-            lua_register(lvm, "progress_done");
-            lua_register(lvm, "progress_step");
+            lua_register(lvm, nameof(print));
+            lua_register(lvm, nameof(progress_init));
+            lua_register(lvm, nameof(progress_done));
+            lua_register(lvm, nameof(progress_step));
 
-            lua_register(lvm, "strpos");
-            lua_register(lvm, "update_view");
-            lua_register(lvm, "select_file");
-            lua_register(lvm, "select_new_file");
+            lua_register(lvm, nameof(strpos));
+            lua_register(lvm, nameof(update_view));
+            lua_register(lvm, nameof(select_file));
+            lua_register(lvm, nameof(select_new_file));
 
             lvm["rtNone"] = (int)GDMRecordType.rtNone;
             lvm["rtIndividual"] = (int)GDMRecordType.rtIndividual;
@@ -118,114 +120,115 @@ private void lua_init(Lua lvm)
             lvm["rtSubmitter"] = (int)GDMRecordType.rtSubmitter;
 
             // any records
-            lua_register(lvm, "get_records_count");
-            lua_register(lvm, "get_record");
-            lua_register(lvm, "get_record_type");
-            lua_register(lvm, "get_record_type_name");
-            lua_register(lvm, "get_record_xref");
-            lua_register(lvm, "get_record_uid");
-            lua_register(lvm, "delete_record");
-            lua_register(lvm, "record_is_filtered");
-            lua_register(lvm, "select_record");
+            lua_register(lvm, nameof(get_records_count));
+            lua_register(lvm, nameof(get_record));
+            lua_register(lvm, nameof(get_record_type));
+            lua_register(lvm, nameof(get_record_type_name));
+            lua_register(lvm, nameof(get_record_xref));
+            lua_register(lvm, nameof(get_record_uid));
+            lua_register(lvm, nameof(delete_record));
+            lua_register(lvm, nameof(record_is_filtered));
+            lua_register(lvm, nameof(select_record));
 
             // any record : notes
-            lua_register(lvm, "get_record_notes_count");
+            lua_register(lvm, nameof(get_record_notes_count));
 
             // any record : multimedia links
-            lua_register(lvm, "get_record_medialinks_count");
-            lua_register(lvm, "get_record_medialink");
-            lua_register(lvm, "set_medialink_primary");
+            lua_register(lvm, nameof(get_record_medialinks_count));
+            lua_register(lvm, nameof(get_record_medialink));
+            lua_register(lvm, nameof(set_medialink_primary));
 
             // any record : bind notes, sources, multimedia
-            lua_register(lvm, "bind_record_note");
-            lua_register(lvm, "bind_record_source");
+            lua_register(lvm, nameof(bind_record_note));
+            lua_register(lvm, nameof(bind_record_source));
 
             // individual records
-            lua_register(lvm, "create_individual");
-            lua_register(lvm, "get_individual_name");
-            lua_register(lvm, "define_sex");
-            lua_register(lvm, "get_individual_sex");
-            lua_register(lvm, "set_individual_sex");
-            lua_register(lvm, "define_patronymic");
-            lua_register(lvm, "get_individual_parents_family");
-            lua_register(lvm, "get_individual_spouses_count");
-            lua_register(lvm, "get_individual_spouse_family");
-            lua_register(lvm, "get_individual_primary_medialink");
+            lua_register(lvm, nameof(create_individual));
+            lua_register(lvm, nameof(get_individual_name));
+            lua_register(lvm, nameof(define_sex));
+            lua_register(lvm, nameof(get_individual_sex));
+            lua_register(lvm, nameof(set_individual_sex));
+            lua_register(lvm, nameof(define_patronymic));
+            lua_register(lvm, nameof(get_individual_parents_family));
+            lua_register(lvm, nameof(get_individual_spouses_count));
+            lua_register(lvm, nameof(get_individual_spouse_family));
+            lua_register(lvm, nameof(get_individual_primary_medialink));
 
             // individual records : associations
-            lua_register(lvm, "get_individual_associations_count");
-            lua_register(lvm, "get_individual_association");
-            lua_register(lvm, "delete_individual_association");
-            lua_register(lvm, "add_individual_association");
+            lua_register(lvm, nameof(get_individual_associations_count));
+            lua_register(lvm, nameof(get_individual_association));
+            lua_register(lvm, nameof(delete_individual_association));
+            lua_register(lvm, nameof(add_individual_association));
 
             // individual records : events
-            lua_register(lvm, "get_individual_events_count");
-            lua_register(lvm, "get_individual_event");
-            lua_register(lvm, "delete_individual_event");
-            lua_register(lvm, "get_individual_event_ex");
+            lua_register(lvm, nameof(get_individual_events_count));
+            lua_register(lvm, nameof(get_individual_event));
+            lua_register(lvm, nameof(delete_individual_event));
+            lua_register(lvm, nameof(get_individual_event_ex));
 
             // individual records : groups
-            lua_register(lvm, "get_individual_groups_count");
-            lua_register(lvm, "get_individual_group");
+            lua_register(lvm, nameof(get_individual_groups_count));
+            lua_register(lvm, nameof(get_individual_group));
 
             // family records
-            lua_register(lvm, "create_family");
-            lua_register(lvm, "bind_family_spouse");
-            lua_register(lvm, "bind_family_child");
-            lua_register(lvm, "get_family_husband");
-            lua_register(lvm, "get_family_wife");
-            lua_register(lvm, "get_family_childs_count");
-            lua_register(lvm, "get_family_child");
+            lua_register(lvm, nameof(create_family));
+            lua_register(lvm, nameof(bind_family_spouse));
+            lua_register(lvm, nameof(bind_family_child));
+            lua_register(lvm, nameof(get_family_husband));
+            lua_register(lvm, nameof(get_family_wife));
+            lua_register(lvm, nameof(get_family_childs_count));
+            lua_register(lvm, nameof(get_family_child));
 
             // note records
-            lua_register(lvm, "create_note");
-            lua_register(lvm, "add_note_text");
+            lua_register(lvm, nameof(create_note));
+            lua_register(lvm, nameof(add_note_text));
 
             // any record with events (individual / family)
-            lua_register(lvm, "create_event");
+            lua_register(lvm, nameof(create_event));
 
             // events
-            lua_register(lvm, "get_event_value");
-            lua_register(lvm, "get_event_place");
-            lua_register(lvm, "get_event_date");
-            lua_register(lvm, "get_event_name");
-            lua_register(lvm, "set_event_value");
-            lua_register(lvm, "set_event_place");
-            lua_register(lvm, "set_event_date");
-            lua_register(lvm, "get_event_year");
+            lua_register(lvm, nameof(get_event_value));
+            lua_register(lvm, nameof(get_event_place));
+            lua_register(lvm, nameof(get_event_date));
+            lua_register(lvm, nameof(get_event_name));
+            lua_register(lvm, nameof(set_event_value));
+            lua_register(lvm, nameof(set_event_place));
+            lua_register(lvm, nameof(set_event_date));
+            lua_register(lvm, nameof(get_event_year));
 
             // source records
-            lua_register(lvm, "create_source");
-            lua_register(lvm, "find_source");
+            lua_register(lvm, nameof(create_source));
+            lua_register(lvm, nameof(find_source));
 
             // group records
-            lua_register(lvm, "create_group");
-            lua_register(lvm, "bind_group_member");
-            lua_register(lvm, "get_group_name");
+            lua_register(lvm, nameof(create_group));
+            lua_register(lvm, nameof(bind_group_member));
+            lua_register(lvm, nameof(get_group_name));
 
             // location records
-            lua_register(lvm, "get_location_usages");
+            lua_register(lvm, nameof(create_location));
+            lua_register(lvm, nameof(get_location_usages));
 
             // csv
-            lua_register(lvm, "csv_load");
-            lua_register(lvm, "csv_close");
-            lua_register(lvm, "csv_get_cols");
-            lua_register(lvm, "csv_get_rows");
-            lua_register(lvm, "csv_get_cell");
-            lua_register(lvm, "csv_create");
-            lua_register(lvm, "csv_write_cell");
+            lua_register(lvm, nameof(csv_load));
+            lua_register(lvm, nameof(csv_close));
+            lua_register(lvm, nameof(csv_get_cols));
+            lua_register(lvm, nameof(csv_get_rows));
+            lua_register(lvm, nameof(csv_get_cell));
+            lua_register(lvm, nameof(csv_create));
+            lua_register(lvm, nameof(csv_write_cell));
 
             // experimental
-            lua_register(lvm, "ado_open");
-            lua_register(lvm, "ado_close");
-            lua_register(lvm, "ado_query_open");
-            lua_register(lvm, "ado_query_close");
-            lua_register(lvm, "ado_query_first");
-            lua_register(lvm, "ado_query_prev");
-            lua_register(lvm, "ado_query_next");
-            lua_register(lvm, "ado_query_last");
-            lua_register(lvm, "ado_get_query_field");
-            lua_register(lvm, "ado_dump");
+            lua_register(lvm, nameof(ado_open));
+            lua_register(lvm, nameof(ado_close));
+            lua_register(lvm, nameof(ado_query_open));
+            lua_register(lvm, nameof(ado_query_close));
+            lua_register(lvm, nameof(ado_query_first));
+            lua_register(lvm, nameof(ado_query_prev));
+            lua_register(lvm, nameof(ado_query_next));
+            lua_register(lvm, nameof(ado_query_last));
+            lua_register(lvm, nameof(ado_get_query_field));
+            lua_register(lvm, nameof(ado_dump));
         }
 
         #endregion
@@ -631,6 +634,17 @@ public object get_family_child(object recPtr, int childIndex)
             return (fam == null) ? null : fBase.Context.Tree.GetPtrValue<GDMRecord>(fam.Children[childIndex]);
         }
 
+        public object create_location(string name, string date)
+        {
+            var loc = fBase.Context.Tree.CreateLocation();
+            var locName = new GDMLocationName() {
+                StringValue = name,
+                Date = { StringValue = date }
+            };
+            loc.Names.Add(locName);
+            return loc;
+        }
+
         public int get_location_usages(object recPtr)
         {
             GDMLocationRecord loc = recPtr as GDMLocationRecord;
@@ -725,7 +739,7 @@ public bool csv_load(string fileName, bool hasHeader)
 
         public bool csv_create(string fileName, int columnsCount, int rowsCount)
         {
-            bool result = false;
+            bool result;
 
             try {
                 fCSVWriter = new CSVWriter();
diff --git a/projects/GKMap/GKMap.WinForms/GMapControl.cs b/projects/GKMap/GKMap.WinForms/GMapControl.cs
index cbcf6a294..b65e80a6e 100644
--- a/projects/GKMap/GKMap.WinForms/GMapControl.cs
+++ b/projects/GKMap/GKMap.WinForms/GMapControl.cs
@@ -965,34 +965,22 @@ void IMapControl.ShowTileGridLines(object go, DrawTile tilePoint)
         void IMapControl.DoMouseClick(MapObject obj, EventArgs e)
         {
             if (obj is MapMarker) {
-                if (OnMarkerClick != null) {
-                    OnMarkerClick(obj as MapMarker, (MouseEventArgs)e);
-                }
+                OnMarkerClick?.Invoke(obj as MapMarker, (MouseEventArgs)e);
             } else if (obj is MapRoute) {
-                if (OnRouteClick != null) {
-                    OnRouteClick(obj as MapRoute, (MouseEventArgs)e);
-                }
+                OnRouteClick?.Invoke(obj as MapRoute, (MouseEventArgs)e);
             } else if (obj is MapPolygon) {
-                if (OnPolygonClick != null) {
-                    OnPolygonClick(obj as MapPolygon, (MouseEventArgs)e);
-                }
+                OnPolygonClick?.Invoke(obj as MapPolygon, (MouseEventArgs)e);
             }
         }
 
         void IMapControl.DoMouseDoubleClick(MapObject obj, EventArgs e)
         {
             if (obj is MapMarker) {
-                if (OnMarkerDoubleClick != null) {
-                    OnMarkerDoubleClick(obj as MapMarker, (MouseEventArgs)e);
-                }
+                OnMarkerDoubleClick?.Invoke(obj as MapMarker, (MouseEventArgs)e);
             } else if (obj is MapRoute) {
-                if (OnRouteDoubleClick != null) {
-                    OnRouteDoubleClick(obj as MapRoute, (MouseEventArgs)e);
-                }
+                OnRouteDoubleClick?.Invoke(obj as MapRoute, (MouseEventArgs)e);
             } else if (obj is MapPolygon) {
-                if (OnPolygonDoubleClick != null) {
-                    OnPolygonDoubleClick(obj as MapPolygon, (MouseEventArgs)e);
-                }
+                OnPolygonDoubleClick?.Invoke(obj as MapPolygon, (MouseEventArgs)e);
             }
         }
 
diff --git a/projects/GKMap/GKMap.WinForms/GMapOverlay.cs b/projects/GKMap/GKMap.WinForms/GMapOverlay.cs
index 458c27580..085a804b4 100644
--- a/projects/GKMap/GKMap.WinForms/GMapOverlay.cs
+++ b/projects/GKMap/GKMap.WinForms/GMapOverlay.cs
@@ -34,27 +34,15 @@ public virtual void OnRender(Graphics g)
                 return;
 
             foreach (MapRoute r in Routes) {
-                if (r.IsVisible) {
-                    var renderable = r as IRenderable;
-                    if (renderable != null)
-                        renderable.OnRender(g);
-                }
+                if (r.IsVisible && r is IRenderable renderable) renderable.OnRender(g);
             }
 
             foreach (MapPolygon p in Polygons) {
-                if (p.IsVisible) {
-                    var renderable = p as IRenderable;
-                    if (renderable != null)
-                        renderable.OnRender(g);
-                }
+                if (p.IsVisible && p is IRenderable renderable) renderable.OnRender(g);
             }
 
             foreach (MapMarker m in Markers) {
-                if (m.IsVisible) {
-                    var renderable = m as IRenderable;
-                    if (renderable != null)
-                        renderable.OnRender(g);
-                }
+                if (m.IsVisible && m is IRenderable renderable) renderable.OnRender(g);
             }
 
             // tooltips above
diff --git a/projects/GKTests/GDModel/GDMAssociationTests.cs b/projects/GKTests/GDModel/GDMAssociationTests.cs
index 7fe1154ba..a487a9ddd 100644
--- a/projects/GKTests/GDModel/GDMAssociationTests.cs
+++ b/projects/GKTests/GDModel/GDMAssociationTests.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -29,7 +29,7 @@ namespace GDModel
     [TestFixture]
     public class GDMAssociationTests
     {
-        private BaseContext fContext;
+        private readonly BaseContext fContext;
 
         public GDMAssociationTests()
         {
diff --git a/projects/GKv2/GKComponents/GKUI/Components/GKDateControl.cs b/projects/GKv2/GKComponents/GKUI/Components/GKDateControl.cs
index a7f5b875f..6df86de8e 100644
--- a/projects/GKv2/GKComponents/GKUI/Components/GKDateControl.cs
+++ b/projects/GKv2/GKComponents/GKUI/Components/GKDateControl.cs
@@ -40,6 +40,8 @@ public class GKDateControl : UserControl, IDateControl, ILocalizable
         private GDMDateType fFixedDateType;
 
 
+        [Browsable(false)]
+        [DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
         public GDMCustomDate Date
         {
             get { return GetDate(); }
diff --git a/projects/plugins/GKCalendarPlugin/HistoryDateBox.cs b/projects/plugins/GKCalendarPlugin/HistoryDateBox.cs
index d31587676..3e5f0e5f0 100644
--- a/projects/plugins/GKCalendarPlugin/HistoryDateBox.cs
+++ b/projects/plugins/GKCalendarPlugin/HistoryDateBox.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -199,14 +199,12 @@ private void SetDate(double value)
 
         private void OnCalendarChanged()
         {
-            var eventHandler = CalendarChanged;
-            if (eventHandler != null) eventHandler(this, new EventArgs());
+            CalendarChanged?.Invoke(this, new EventArgs());
         }
 
         private void OnDateChanged()
         {
-            var eventHandler = DateChanged;
-            if (eventHandler != null) eventHandler(this, new EventArgs());
+            DateChanged?.Invoke(this, new EventArgs());
         }
 
         private void cmbCalendar_SelectedIndexChanged(object sender, EventArgs e)
diff --git a/projects/plugins/GKHistoryDataPlugin/HistoryData.cs b/projects/plugins/GKHistoryDataPlugin/HistoryData.cs
index 73c81c6d7..04827dfcf 100644
--- a/projects/plugins/GKHistoryDataPlugin/HistoryData.cs
+++ b/projects/plugins/GKHistoryDataPlugin/HistoryData.cs
@@ -1,6 +1,7 @@
-/*
+
+/*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -18,8 +19,6 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#pragma warning disable SYSLIB0014
-
 using System;
 using System.Collections.Generic;
 using System.IO;
diff --git a/projects/plugins/GKLifePlugin/ConwayLife/LifeViewer.cs b/projects/plugins/GKLifePlugin/ConwayLife/LifeViewer.cs
index 18603bb3e..7257f8350 100644
--- a/projects/plugins/GKLifePlugin/ConwayLife/LifeViewer.cs
+++ b/projects/plugins/GKLifePlugin/ConwayLife/LifeViewer.cs
@@ -168,7 +168,7 @@ protected void Change()
         {
             Invalidate();
 
-            if (fOnChange != null) fOnChange(this);
+            fOnChange?.Invoke(this);
         }
 
         protected override void OnMouseMove(MouseEventArgs e)
diff --git a/projects/plugins/GKStdReports/AncestorStatisticsReport.cs b/projects/plugins/GKStdReports/AncestorStatisticsReport.cs
index 6bd252d85..f5d09ef52 100644
--- a/projects/plugins/GKStdReports/AncestorStatisticsReport.cs
+++ b/projects/plugins/GKStdReports/AncestorStatisticsReport.cs
@@ -1,6 +1,6 @@
 /*
  *  "GEDKeeper", the personal genealogical database editor.
- *  Copyright (C) 2009-2023 by Sergey V. Zhdanovskih.
+ *  Copyright (C) 2009-2024 by Sergey V. Zhdanovskih.
  *
  *  This file is part of "GEDKeeper".
  *
@@ -113,13 +113,13 @@ public ConsanguinityInfo(GDMIndividualRecord indi)
             }
         }
 
-        private Dictionary<string, ConsanguinityInfo> fConsanguinityCommonIndiMap = new Dictionary<string, ConsanguinityInfo>();
+        private readonly Dictionary<string, ConsanguinityInfo> fConsanguinityCommonIndiMap = new Dictionary<string, ConsanguinityInfo>();
         private double fConsanguinityFactor;
-        private List<GenerationInfo> fGenerations = new List<GenerationInfo>();
-        private Dictionary<string, GDMIndividualRecord> fImplexCommonIndiMap = new Dictionary<string, GDMIndividualRecord>();
+        private readonly List<GenerationInfo> fGenerations = new List<GenerationInfo>();
+        private readonly Dictionary<string, GDMIndividualRecord> fImplexCommonIndiMap = new Dictionary<string, GDMIndividualRecord>();
         private double fImplexFactor;
-        private HashSet<string> fIndiSet = new HashSet<string>();
-        private HashSet<string> fCommonAncestorSet = new HashSet<string>();
+        private readonly HashSet<string> fIndiSet = new HashSet<string>();
+        private readonly HashSet<string> fCommonAncestorSet = new HashSet<string>();
 
         private void ClearStats()
         {
diff --git a/projects/plugins/GKTreeSyncPlugin/clean.cmd b/projects/plugins/GKTreeSyncPlugin/clean.cmd
new file mode 100644
index 000000000..45dfcfb5e
--- /dev/null
+++ b/projects/plugins/GKTreeSyncPlugin/clean.cmd
@@ -0,0 +1,3 @@
+rmdir .\.vs /s /q 2>NUL
+rmdir .\bin /s /q 2>NUL
+rmdir .\obj /s /q 2>NUL