text disappears at edges of text box.

I keep getting this problem. Text disappears out of a text box and I can't seem to find a consistent way to avoid it.  You can see the 'not here' has gone

If I pull the vector motion left then I can get the whole text - but I don't want it left. SO if I move the text box right to compensate then it disappears again. If I try reducing the font size, and chagning the various scales but that doesn't help.

I often seem to have this problem and sometimes I can fix it by just messing around - but I'd like to know what is going to and how to solve it properly please. 

Thanks

Hi - I keep coming up against this problem in various projects. I 7