One-handed operation: Use for all screens mode (tiny screen mode) doesn't work on Galaxy Note 3 I have read all of the instructions I can find and watched several videos on how to turn on this feature and use it.

After enabling the feature in settings>controls>On-handed operation>Use for all screens, and trying the back and forth quick swipe on several apps...I still can't make this work.

Are there some competing settings or apps that disallow use of this feature?

Thanks for your help.
Try upgrading to Android 4.4.2. Settings -> general -> about device -> Software update -> update.

:)