I recently completed my first glue-up of a frame and panel door. I used "space balls" to allow for expansion/contraction of the panel. However, I think that when I clamped the door after gluing, some of the glue from the rail and stile joints squeezed into the space at each corner of the panel between the top of the panel and the bottom of the rail (or the bottom of the panel and the top of the rail for the bottom rail). If so, the "space balls" seem like wasted effort since the panel is now glued to the rail and/or stile at each corner of the panel.
I will appreciate any advice regarding the proper way to glue the stiles and rails without glue squeezing onto the corners of the free floating panel. The only suggestion I found in the archives was to place wax paper between the panel and the rails/stiles. I am hoping there is a better solution.