Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: I notice there is nothing to hold the mattress in, to prevent it from sliding forward. Does that have a tendency to happen at all?
Document: My wife decided she wanted and after a lot of looking she decided on this one. It does come unfinished and there were just a few dings or what not. Nothing major that we needed to replace or return. It was pretty simple to put together. Took maybe 30 minutes but you really need two people. Mostly just for one to hold as the other screws it together and then when attaching the two major parts.
I love this frame it fits perfectly with my mozaic mattress. Being a pretty big dude i was worried if it hold up, after about a month it still solid as ever. I built it on my own so don't worry about it being hard to build. I love this frame which has replaced my old bed and i love it.
The futon frame arrived in two boxes. It had all the parts (plus a few extra pieces of hardware, which is nice). The only thing that I'm a little disappointed in is that the seat seems to be a bit more shallow than our last frame (which this replaced). It's solid wood. It was fairly easy to put together, and it looks very clean and neutral. We're almost happy.The biggest bummer about this frame is that there is nothing to keep the mattress in place.
I would recommend putting some wax on the joints to prevent squeaking, and tightening the hardware a few times a year.
If you don't want an awkward tall looking futon stick with the full. I love my futon it's great, but it looks awful funny being that the back size is very tall against the wall... another review someone wished it hadn't been so deep... this is deep. Other than that i have nothing but great things to say about my futon, the quality is nice, it's easy to assemble, it's easy to use, it's lighter, and it's not a stupid metal futon frame from walmart.
It took my two sisters and I only about 1 1/2 hours to assemble this futon, and there was only one point (lifting the back onto the slots) in which we found the instructions totally confusing -- a simple close-up drawing of this part of the assembly process would have greatly helped. I would definitely recommend two people, minimum, to do the assembly, just so you have the extra pair of hands needed to hold one part steady while adding another part.
Very pleased with this product -- its just what I wanted. I had a friend assemble it though ... I bought the mattress and cover from same place
It sits up a little higher so feels more like regular sofa with much better sleeping support also. I recommend using an innerspring mattress for better long term use as we have had both kinds. It will last much longer!
I am very pleased and impressed with this piece of furniture. The poplar is nice looking and almost without blemish. Some of the boards may have a greenish hue- the manufacturer claims it will fade to light brown over time, or with 20-30 minutes in direct sunlight. The sunlight trick didn't really work for me. Doesn't matter though- 90% of the frame is hidden under the mattress and will never be seen.
I bought this frame a year ago and it's still amazing. Such a great price for a quality piece of furniture. Putting it together was very easy as long as you can follow instructions. Unfortunately, I didn't realize how heavy the wood and the mattress would be to lift into couch mode, so I keep it as a bed most of the time. I wouldn't recommend it unless you keep it one way most of the time or are very strong.
Answer: Yes it does, but I bought a high end 9'' thick mattress. I added some of those futon strips and it has helped. We do not use it much for sitting on. The main purpose of buying it was to use in a small office/bedroom as a guest bed. My other suggestion is a bit more work, but definitely works well. Sew some canvas strips to the back of the mattress and tie them to the upper part of the back and lower front of the seat. My sister has this same futon frame and swears by adding those ties.