My question involves a child custody case from the State of: Kansas

I have been divorced for 7 years and have a 13 yr old daughter and 8 yr old son. My ex-wife has always dictated where the kids would go to school and I never challenged her decisions so that they kids would not get pulled into a dispute. We have 50-50 custody of the kids and up until 5 months ago, the kids attended 2 schools between 2 blocks and 1 miles from where my ex lives. I live 16 miles away from their schools so on the days I had them it meant 32 miles round trip to drop them off and another 32 to pick them up.

About 5 months ago my 13 yr old daughter began getting into trouble while at my ex's place. Her grades began to slip and she was becoming involved in a bad group of kids. She began lying to my ex regarding where she was at and was able to get away with a lot since there was 3 hours between when my daughter got out of school and when my ex would get home from work. The straw that broke my back was when my daughter confided in my wife that she had had sex with a boy. It was clear to me that my wife was not providing good supervision so I went and got her out of school and brought her to my house.

I spoke to my ex and her husband and it was decided that my daughter would go to school out here in my school district. Since then her grades are straight A's, her teachers have nothing but great things to say about her, she dresses better and is just a better person.

I discovered last week that my ex has been telling my daughter that she will probably go back to my ex's school district after this school year so that she can start high school down there? This is crazy. Why would she want to pull my daughter back down to a school the same kids are that she got into trouble with. Not only that, why pull my daughter away from a school she is doing outstanding at? The reason is, my ex wants to show me that she has more control and is also bitter that we were able to fix my daughters problems that were created while under her care.

So my question is, if we already have her enrolled in high school out here, can my ex just decide for herself to pull her out and enroll her elsewhere? If that is the case, in theory I could go right back down, pull her out and re-enroll her up here again. This can get very messy. Also, if I wanted to take her to court to have a judge decide the matter, wouldn't I really be taking her in to prevent her from doing something she hasn't done yet? I mean, how can I stop her from pulling this stunt until she actually goes through with it?