This has always been a bit of a problem.
The easiest solution, is to curser down the page before you start and then enter the latex in the middle of it so that the curser has already been above and below the entry point.
If you forget to do this you can click on the Latex and have the yellow box come up then hit the arrow key twice to place the curser after the LaTex. then hit return and it will take you to the next line.
Another method, an afterthought method like the first, is to cut the Latex then add more lines then paste the latex back in half way down so that your curser has already been below and above it.
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Also remember when you use Latex add something not in Latex above it.
I often put 'Like this' or something similar.
If the post only contains latex and nothing else then it causes entry problems.
