It is easy to make track longer but I did not understand what do you mean by and the box that comes up when you push record
Refer screen shot Music Maker 16 Premium(same method in Music Maker 17 surely)Audio recording in this screen shot is just for reference.(I had made that for another answer)
In the screen shot on top yellow Bar you need to increase or decrease. Then look at No.1 in green, red arrow indicating (-)minus mark click on it then follow No.2 in green pull that bar to right to increase or you can also pull to left to decrease. If you want to adjust the length of screen after that just click on double arrow under No.1 in green.
In short
To add more area click on Minus mark (Pull bar to left or right)
To adjust screen doubble arrow.
All details are available in the Pdf help file of Music Maker.