Some progress made, but potential version mess.

.gitignore

@@ -65,8 +65,8 @@ SuiteCRMAddIn/Documentation/latex/
 
 *.pcapng
 
-*.vsp
+*.xlsx
 
 *.psess
 
-*.xlsx
+*.vsp

SuiteCRMAddIn/BusinessLogic/AppointmentSyncState.cs

@@ -29,6 +29,8 @@ namespace SuiteCRMAddIn.BusinessLogic
     using Outlook = Microsoft.Office.Interop.Outlook;
     using System;
     using System.Collections.Generic;
+    using System.Runtime.InteropServices;
+    using SuiteCRMClient.Logging;
 
     public class AppointmentSyncState: SyncState<Outlook.AppointmentItem>
     {
@@ -87,51 +89,6 @@ public override void DeleteItem()
             this.OutlookItem.Delete();
         }
 
-
-        /// <summary>
-        /// An appointment may be changed because its recipients have changed.
-        /// </summary>
-        /// <returns>True if the underlying item has changed, or its recipients have changed.</returns>
-        protected override bool ReallyChanged()
-        {
-            var result = base.ReallyChanged();
-
-            ProtoItem older = this.Cache as ProtoAppointment;
-
-            if (older != null)
-            {
-                var currentAddresses = new HashSet<string>();
-                var olderAddresses = new List<string>();
-                olderAddresses.AddRange(((ProtoAppointment)older).RecipientAddresses);
-
-                foreach (Outlook.Recipient recipient in olItem.Recipients)
-                {
-                    currentAddresses.Add(recipient.GetSmtpAddress());
-                }
-                if (currentAddresses.Count == olderAddresses.Count)
-                {
-                    var sorted = new List<string>();
-                    sorted.AddRange(currentAddresses);
-                    sorted.Sort();
-
-                    for (int i = 0; i < sorted.Count; i++)
-                    {
-                        if (sorted[i] != olderAddresses[i])
-                        {
-                            result = true;
-                            break;
-                        }
-                    }
-                }
-                else
-                {
-                    result = true;
-                }
-            }
-
-            return result;
-        }
-
         /// <summary>
         /// Construct a JSON-serialisable representation of my appointment item.
         /// </summary>

SuiteCRMAddIn/BusinessLogic/ContactSyncState.cs

@@ -26,6 +26,8 @@ namespace SuiteCRMAddIn.BusinessLogic
     using SuiteCRMAddIn.ProtoItems;
     using Extensions;
     using Outlook = Microsoft.Office.Interop.Outlook;
+    using System.Runtime.InteropServices;
+    using SuiteCRMClient.Logging;
 
     /// <summary>
     /// A SyncState for Contact items.
@@ -54,6 +56,7 @@ public override string Description
             }
         }
 
+
         /// <summary>
         /// Don't actually delete contact items from Outlook; instead, mark them private so they
         /// don't get copied back to CRM.

SuiteCRMAddIn/BusinessLogic/SyncState.cs

@@ -69,20 +69,23 @@ public bool IsDeletedInOutlook
         {
             get
             {
+                bool result;
                 if (_wasDeleted) return true;
                 // TODO: Make this logic more robust. Perhaps check HRESULT of COMException?
                 try
                 {
                     // Has the side-effect of throwing an exception if the item has been deleted:
                     var entryId = OutlookItemEntryId;
-                    return false;
+                    result = false;
                 }
                 catch (COMException com)
                 {
-                    Globals.ThisAddIn.Log.Debug($"Object has probably been deleted: {com.ErrorCode}, {com.Message}");
+                    Globals.ThisAddIn.Log.Debug($"Object has probably been deleted: {com.ErrorCode}, {com.Message}; HResult {com.HResult}");
                     _wasDeleted = true;
-                    return true;
+                    result = true;
                 }
+
+                return result;
             }
         }
 

SuiteCRMAddIn/BusinessLogic/SyncState{1}.cs

@@ -25,6 +25,7 @@ namespace SuiteCRMAddIn.BusinessLogic
     using SuiteCRMAddIn.ProtoItems;
     using SuiteCRMClient.Logging;
     using System;
+    using System.Runtime.InteropServices;
 
     /// <summary>
     /// The sync state of an item of the specified type.

SuiteCRMAddIn/BusinessLogic/Synchroniser.cs

@@ -786,18 +786,44 @@ protected void EnsureSynchronisationPropertiesForOutlookItem(OutlookItemType olI
         /// <param name="value">The value.</param>
         protected abstract void EnsureSynchronisationPropertyForOutlookItem(OutlookItemType olItem, string name, string value);
 
+        /// <summary>
+        /// Returns true iff user is currently focussed on this (Contacts/Appointments/Tasks) tab.
+        /// </summary>
+        /// <remarks>
+        /// This is used in determining whether an item is in fact newly created by the user;
+        /// it has a certain code smell to it.
+        /// </remarks>
+        protected abstract bool IsCurrentView { get; }
+
+        /// <summary>
+        /// Returns true iff local (Outlook) deletions should be propagated to the server.
+        /// </summary>
+        /// <remarks>TODO: Why should this ever be false?</remarks>
+        protected abstract bool PropagatesLocalDeletions { get; }
+
         /// <summary>
         /// Deal, in CRM, with items deleted in Outlook.
         /// </summary>
         protected void RemoveDeletedItems()
         {
-            // Make a copy of the list to avoid mutation error while iterating:
-            var syncStatesCopy = new List<SyncState<OutlookItemType>>(ItemsSyncState);
-            foreach (var syncState in syncStatesCopy)
+            if (IsCurrentView && PropagatesLocalDeletions)
             {
-                var shouldDeleteFromCrm = syncState.IsDeletedInOutlook || !syncState.ShouldSyncWithCrm;
-                if (shouldDeleteFromCrm) RemoveFromCrm(syncState);
-                if (syncState.IsDeletedInOutlook) ItemsSyncState.Remove(syncState);
+                // Make a copy of the list to avoid mutation error while iterating:
+                var syncStatesCopy = new List<SyncState<OutlookItemType>>(ItemsSyncState);
+                foreach (var syncState in syncStatesCopy)
+                {
+                    var shouldDeleteFromCrm = syncState.IsDeletedInOutlook || !syncState.ShouldSyncWithCrm;
+                    if (shouldDeleteFromCrm) RemoveFromCrm(syncState);
+                    if (syncState.IsDeletedInOutlook) ItemsSyncState.Remove(syncState);
+                }
+            }
+            else
+            {
+                var items = ItemsSyncState.Where(x => x.IsDeletedInOutlook).Count();
+                if (items > 0)
+                {
+                    Log.Error($"Possibly bug #95: was attempting to delete {items} items from CRM");
+                }
             }
         }
 
@@ -1071,7 +1097,7 @@ protected virtual void OutlookItemAdded(OutlookItemType olItem)
                     {
                         lock (enqueueingLock)
                         {
-                            if (this.GetExistingSyncState(olItem) == null)
+                            if (IsCurrentView && this.GetExistingSyncState(olItem) == null)
                             {
                                 SyncState<OutlookItemType> state = this.AddOrGetSyncState(olItem);
                                 DaemonWorker.Instance.AddTask(new TransmitNewAction<OutlookItemType>(this, state, this.DefaultCrmModule));
@@ -1179,7 +1205,7 @@ protected void RemoveItemSyncState(SyncState<OutlookItemType> item)
         /// <returns>True if this synchroniser relates to the current tab and the timing logic is satisfied.</returns>
         protected bool ShouldPerformSyncNow(SyncState<OutlookItemType> syncState)
         {
-            return (syncState.ShouldPerformSyncNow());
+            return (IsCurrentView && syncState.ShouldPerformSyncNow());
         }
     }
 

SuiteCRMAddIn/BusinessLogic/TaskSyncState.cs

@@ -26,6 +26,7 @@ namespace SuiteCRMAddIn.BusinessLogic
     using ProtoItems;
     using Extensions;
     using Outlook = Microsoft.Office.Interop.Outlook;
+    using System.Runtime.InteropServices;
 
     /// <summary>
     /// A SyncState for Contact items.
@@ -52,6 +53,7 @@ public override string Description
             }
         }
 
+
         public override void DeleteItem()
         {
             this.OutlookItem.Delete();