diff --git a/NinchatSDK/UI/ViewControllers/ChatViewController/ChatView/NINChatView.m b/NinchatSDK/UI/ViewControllers/ChatViewController/ChatView/NINChatView.m
index 39138af..59fb1ab 100644
--- a/NinchatSDK/UI/ViewControllers/ChatViewController/ChatView/NINChatView.m
+++ b/NinchatSDK/UI/ViewControllers/ChatViewController/ChatView/NINChatView.m
@@ -160,6 +160,8 @@ -(void) setSessionManager:(NINSessionManager*)sessionManager {
 
 -(void) newMessageWasAddedAtIndex:(NSInteger)index {
     runOnMainThread(^{
+        if ([self.tableView numberOfRowsInSection:0] >= [self.dataSource numberOfMessagesForChatView:self]) { return; }
+
         [self.tableView beginUpdates];
         [self.tableView insertRowsAtIndexPaths:@[[NSIndexPath indexPathForRow:index inSection:0]] withRowAnimation:UITableViewRowAnimationAutomatic];
         [self.tableView endUpdates];
@@ -168,6 +170,8 @@ -(void) newMessageWasAddedAtIndex:(NSInteger)index {
 
 -(void) messageWasRemovedAtIndex:(NSInteger)index {
     runOnMainThread(^{
+        if ([self.tableView numberOfRowsInSection:0] <= [self.dataSource numberOfMessagesForChatView:self]) { return; }
+
         [self.tableView beginUpdates];
         [self.tableView deleteRowsAtIndexPaths:@[[NSIndexPath indexPathForRow:index inSection:0]] withRowAnimation:UITableViewRowAnimationAutomatic];
         [self.tableView endUpdates];
diff --git a/NinchatSDK/UI/ViewControllers/ChatViewController/NINChatViewController.m b/NinchatSDK/UI/ViewControllers/ChatViewController/NINChatViewController.m
index 0ed6eaa..f674890 100644
--- a/NinchatSDK/UI/ViewControllers/ChatViewController/NINChatViewController.m
+++ b/NinchatSDK/UI/ViewControllers/ChatViewController/NINChatViewController.m
@@ -7,6 +7,7 @@
 //
 
 @import CoreServices;
+@import MobileCoreServices;
 @import AVFoundation;
 @import AVKit;
 @import Photos;
@@ -391,13 +392,15 @@ -(void) listenToWebRTCSignaling {
 
                 // Show the video view
                 [weakSelf adjustConstraintsForSize:weakSelf.view.bounds.size animate:YES];
-                [self resizeLocalVideoView];
+                [weakSelf resizeLocalVideoView];
+                [weakSelf stopIdleTimer:YES];
             }];
         } else if ([note.userInfo[@"messageType"] isEqualToString:kNINMessageTypeWebRTCHangup]) {
             NSLog(@"Got WebRTC hang-up - closing the video call.");
 
             // Disconnect
             [weakSelf disconnectWebRTC];
+            [weakSelf stopIdleTimer:NO];
 
             // Close the video view
             [weakSelf adjustConstraintsForSize:weakSelf.view.bounds.size animate:YES];
@@ -861,6 +864,14 @@ -(void) keyboardWillHide:(NSNotification *)notification {
     [self.sessionManager setIsWriting:NO completion:^(NSError* error) {}];
 }
 
+#pragma mark - Helper
+
+/// To prevent screen-saver during a video call
+/// https://github.com/somia/mobile/issues/204
+- (void) stopIdleTimer:(BOOL )stop {
+    [UIApplication sharedApplication].idleTimerDisabled = stop;
+}
+
 #pragma mark - Lifecycle etc.
 
 -(void) viewWillAppear:(BOOL)animated {
@@ -981,7 +992,7 @@ -(void) viewDidLoad {
         NSNumber* index = note.userInfo[@"index"];
         if ([note.userInfo[@"action"] isEqualToString:@"insert"]) {
             [weakSelf.chatView newMessageWasAddedAtIndex:index.integerValue];
-        } else {
+        } else if ([note.userInfo[@"action"] isEqualToString:@"remove"]) {
             [weakSelf.chatView messageWasRemovedAtIndex:index.integerValue];
         }