[TIMOB-14488] Stop hammering the tableView with updateRow calls during a layout pass
timob-14487: Add duplicate check when adding dialogs to activity
Merge pull request #4442 from hieupham007/timob-14487-3_1_X

timob-14487: Add duplicate check when adding dialogs to activity
Merge pull request #4440 from vishalduggal/timob-14488-31X

[TIMOB-14488] (3_1_X) Stop hammering the tableView with updateRow calls during a layout pass

Tested and verified using the same steps as in the video "iPhone 20130626.mp4" attached to the bug report. The app is no longer sluggish and does not become unresponsive.