Respond to CR.

// FREEBIE

Signal/src/ViewControllers/ConversationView/MessagesViewController.m

@@ -2186,7 +2186,7 @@ typedef enum : NSUInteger {
 {
     OWSAssert(!self.isUserScrolling);
 
-    BOOL hasMoreUnseenMessages = self.dynamicInteractions.hasMoreUnseenMessages;
+    BOOL hasEarlierUnseenMessages = self.dynamicInteractions.hasMoreUnseenMessages;
 
     // We want to restore the current scroll state after we update the range, update
     // the dynamic interactions and re-layout.  Here we take a "before" snapshot.
@@ -2234,7 +2234,10 @@ typedef enum : NSUInteger {
     self.collectionView.contentOffset = CGPointMake(0, self.collectionView.contentSize.height - scrollDistanceToBottom);
 
     [self.scrollLaterTimer invalidate];
-    if (hasMoreUnseenMessages) {
+    // Don’t auto-scroll after “loading more messages” unless we have “more unseen messages”.
+    //
+    // Otherwise, tapping on "load more messages" autoscrolls you downward which is completely wrong.
+    if (hasEarlierUnseenMessages) {
         // We want to scroll to the bottom _after_ the layout has been updated.
         self.scrollLaterTimer = [NSTimer weakScheduledTimerWithTimeInterval:0.001f
                                                                      target:self

Signal/src/util/ThreadUtil.h

@@ -23,7 +23,7 @@ NS_ASSUME_NONNULL_BEGIN
 // This is used by MessageViewController to increase the
 // range size of the mappings (the load window of the conversation)
 // to include the unread indicator.
-@property (nonatomic, nullable) NSNumber *unreadIndicatorPosition;
+@property (nonatomic, nullable, readonly) NSNumber *unreadIndicatorPosition;
 
 // If there are unseen messages in the thread, this is the timestamp
 // of the oldest unseen messaage.
@@ -34,9 +34,9 @@ NS_ASSUME_NONNULL_BEGIN
 // repeatedly. The unread indicator should continue to show up until
 // it has been cleared, at which point hideUnreadMessagesIndicator is
 // YES in ensureDynamicInteractionsForThread:...
-@property (nonatomic, nullable) NSNumber *firstUnseenInteractionTimestamp;
+@property (nonatomic, nullable, readonly) NSNumber *firstUnseenInteractionTimestamp;
 
-@property (nonatomic) BOOL hasMoreUnseenMessages;
+@property (nonatomic, readonly) BOOL hasMoreUnseenMessages;
 
 - (void)clearUnreadIndicatorState;
 

Signal/src/util/ThreadUtil.m

@@ -18,6 +18,18 @@
 
 NS_ASSUME_NONNULL_BEGIN
 
+@interface ThreadDynamicInteractions ()
+
+@property (nonatomic, nullable) NSNumber *unreadIndicatorPosition;
+
+@property (nonatomic, nullable) NSNumber *firstUnseenInteractionTimestamp;
+
+@property (nonatomic) BOOL hasMoreUnseenMessages;
+
+@end
+
+#pragma mark -
+
 @implementation ThreadDynamicInteractions
 
 - (void)clearUnreadIndicatorState