Bug 29364 - ListView group headers missing after adding items.
Summary: ListView group headers missing after adding items.
Alias: None
Product: Forms
Classification: Xamarin
Component: iOS ()
Version: 1.4.2
Hardware: PC Mac OS
: Normal normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2015-04-23 19:53 UTC by Jon Goldberger [MSFT]
Modified: 2015-07-10 09:14 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

Test Project (757.49 KB, application/zip)
2015-04-23 19:53 UTC, Jon Goldberger [MSFT]

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Description Jon Goldberger [MSFT] 2015-04-23 19:53:11 UTC
Created attachment 10887 [details]
Test Project

## Description

On iOS, when adding items quickly to a ListView whose source is an ObservableCollection and has Group Headers, the Group Headers disappear, though they do seem to come back after a bit of scrolling. On the meantime, scrolling is still odd and it seems that some items are blank... but those too eventually seem to come back after scrolling _slowly_ through the list. Which makes me think this _might_ be related to bug #29060 and/or bug #28061, but since neither of those directly speak about group headers, I filed this new bug report.

## Steps to reproduce

1. Open the attached test project, restore packages and deploy to iOS simulator (test on 5s 8.3 simulator)

2. Scroll to the bottom of the list.

3. Quickly tap the Add Item button a few times repeatedly.

4. Scroll quickly through list.

Expected result: ListView will have new items added and all group headers and items shown as I scroll through the list.

Actual result: During step 3, I see the Group header disappear. Then scrolling quickly, I see some blank space where items should be displayed.

>Screencast: http://screencast.com/t/PfzhSsq0Wy

## Notes

Again, scrolling slowly through the list seems to allow the ListView to update itself properly and eventually all of the items and group headers will be shown again. At least that is what I experienced consistently.

Tested with both Forms 1.4.1 and 1.4.2. Same results.

## My Environment

=== Xamarin Studio ===

Version 5.8.3 (build 1)
Installation UUID: 2dc9022f-f9a8-424f-8284-bf224cbbfde0
	Mono 3.12.1 ((detached/0849ec7)
	GTK+ 2.24.23 (Raleigh theme)

	Package version: 312010003

=== Apple Developer Tools ===

Xcode 6.3.1 (7703)
Build 6D1002

=== Xamarin.iOS ===

Version: (Business Edition)
Hash: f7736a4
Build date: 2015-04-09 04:22:08-0400

=== Xamarin.Android ===

Version: (Business Edition)
Android SDK: /Users/apple/Library/Developer/Xamarin/android-sdk-mac_x86
	Supported Android versions:
		2.2    (API level 8)
		2.3    (API level 10)
		3.1    (API level 12)
		4.0    (API level 14)
		4.0.3  (API level 15)
		4.1    (API level 16)
		4.2    (API level 17)
		4.3    (API level 18)
		4.4    (API level 19)
		4.4.87 (API level 20)
		5.0    (API level 21)
Java SDK: /usr
java version "1.6.0_65"
Java(TM) SE Runtime Environment (build 1.6.0_65-b14-466.1-11M4716)
Java HotSpot(TM) 64-Bit Server VM (build 20.65-b04-466.1, mixed mode)

=== Xamarin Android Player ===

Version: Unknown version
Location: /Applications/Xamarin Android Player.app

=== Xamarin.Mac ===

Version: (Business Edition)

=== Build Information ===

Release ID: 508030001
Git revision: 6e8e725e0d689351901c2c70453bfa4ea25e293b
Build date: 2015-04-06 20:31:47-04
Xamarin addins: 051cd5f8c1b5dbfc87eaef80a74aec03f34c60a8

=== Operating System ===

Mac OS X 10.10.3
Darwin Jons-iMac.local 14.3.0 Darwin Kernel Version 14.3.0
    Mon Mar 23 11:59:05 PDT 2015
    root:xnu-2782.20.48~5/RELEASE_X86_64 x86_64
Comment 2 Jason Smith [MSFT] 2015-05-20 20:47:33 UTC
This should be fixed in the next release
Comment 3 Parmendra Kumar 2015-07-10 09:14:22 UTC
I have checked this issue with Xamarin.Forms and its working fine.

Hence closing this issue.