[fintstone]

Easiest way is to fix it at the bottom. It is likely moving too much. Most have floor brackets you can use already built in. They are pretty rigid and accept a substantial lag bolt that will hold it in place just fine. Make sure it is well anchored at the floor mounts ...it is easier to drill floor/tile (if not already done). you can also use the adjusters at floor to raise to make fit at top tighter. If it has floor mounts and you do that well, you typically will not need the anchor bar.