Behavioural problems (motion) / how do you stop actors leaving the scene? / Mysterious text disappea

I’ve been toying around with settings for ages now. I have a minigame inside a larger game where there are 3 spaceships(smooth spaceship) shooting(baseball) at you(good spaceship) and you have to get to a particular actor. Two of the ships work perfectly. The arrangement is that there is one spaceship moving the length of the screen and back and another two underneath travelling half the length. One ship on the bottom works perfectly, but the other ship moves off the scene and doesn’t come back. I have even set this ship to behave like the other ship but reversed the direction, but nothing changes. Then the actor you are supposed to get to wanders off the other way, then the good spaceship disappears. How do I get the trouble actors to stop disappearing off the scene, and what can I do about this motion problem?

Also, I tested my game out a while ago, looked back at all the main scenes and the text in all but one of them was gone! What is the reason for this and how can I prevent it?

Lastly how do you get text to overlap with actors?

To solve the motion  problem, you could try putting walls at both sides and have the actor stop  when it collides with the wall.I’ve noticed that the text  from the intro, won, lost, and instructions scenes seemed to all change when I changed one.  Not sure if there is a defect in the game  creater UI.You can have text overlap with actors  by setting the z-index property higher for the actor  you want to appear on top.  If the text is part of the actor, you can change the XAML to position the text over the rest of the actor./