What I expected to happen was...:
I would be able to select the world I wanted to open and it would load up.

What actually happened was...:
I was unable to select a world (highlight it) using any method from the touchscreen. I have tried using an onscreen touchpad and my fingers.
Only with the aid of an external mouse it is possible to select a single player world.

It looks like thousands of other players have the same problem:
http://www.minecraftforum.net/forums/support/unmodified-minecraft-client/1867171-windows-8-tablet-pc-issue-cant-select-an-existing
http://www.minecraftforum.net/forums/support/unmodified-minecraft-client/1863715-minecraft-not-working-on-hp-split-x2
http://www.minecraftforum.net/topic/1974036-cant-select-world-162/
https://answers.yahoo.com/question/index?qid=20131230184900AAe8moq
https://answers.yahoo.com/question/index?qid=20130814195328AALOl9t

Steps to Reproduce:
1. Open Minecraft on a touch 2 in 1 pc. The one on the forum (hp split x2) will most likely produce the outcome.
2. Try to select a world from the world selection screen using either an onscreen touchpad or fingers.
3. You should not be able to select a single player world without an external mouse.