Small improvement

app/src/main/java/eu/faircode/email/Core.java

@@ -2775,9 +2775,9 @@ class Core {
         boolean alert_once = prefs.getBoolean("alert_once", true);
 
         // Get contact info
-        Map<TupleMessageEx, ContactInfo> messageContact = new HashMap<>();
+        Map<Long, ContactInfo> messageContact = new HashMap<>();
         for (TupleMessageEx message : messages)
-            messageContact.put(message, ContactInfo.get(context, message.account, message.from, false));
+            messageContact.put(message.id, ContactInfo.get(context, message.account, message.from, false));
 
         // Summary notification
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N || notify_summary) {
@@ -2846,7 +2846,8 @@ class Core {
                     DateFormat DTF = Helper.getDateTimeInstance(context, SimpleDateFormat.SHORT, SimpleDateFormat.SHORT);
                     StringBuilder sb = new StringBuilder();
                     for (EntityMessage message : messages) {
-                        sb.append("<strong>").append(messageContact.get(message).getDisplayName(name_email)).append("</strong>");
+                        ContactInfo info = messageContact.get(message.id);
+                        sb.append("<strong>").append(info.getDisplayName(name_email)).append("</strong>");
                         if (!TextUtils.isEmpty(message.subject))
                             sb.append(": ").append(message.subject);
                         sb.append(" ").append(DTF.format(message.received));
@@ -2870,7 +2871,7 @@ class Core {
 
         // Message notifications
         for (TupleMessageEx message : messages) {
-            ContactInfo info = messageContact.get(message);
+            ContactInfo info = messageContact.get(message.id);
 
             // Build arguments
             long id = (message.content ? message.id : -message.id);