It is poor design. In fact I don't think they think thru or test anything they install into many RV's.
You have a lid that doesn't stay up. That's not your fault. Who tries toilet lids when buying an RV.
I bought by first TT as a newbie and didn't realize until my first camping trip with it that you couldn't close the bathroom door when sitting on the toilet because your knees prevented the door from closing. :R:R
On my second purchase of an RV when the salesman started telling me how great the kitchen cabinets looked I pushed him aside and headed straight for the bathroom to see if I could use it with the door closed! :B
Sadly no matter what the price, many of the RV's I looked at where the toilet was located, if you were over 5 foot tall your knees 'would' hit the door.
So if anyone in your camping family is over 5 ft tall 'sit on' and 'try out' the toilet BEFORE you buy! :B