I'd like to have the ability for partial freezing that would work similarly to band strength in that you can control the strength of the freeze. This could be helpful in those times when you are perhaps following a pattern, know that a section is almost completely fine where it is, but want to make larger improvements on a certain section while still leaving a 'partially frozen' area susceptible to some minor wiggling or tweaking, etc. It could also work for general handwork where you want some give from the core of the puzzle during a more drastic pull to a smaller, unfrozen section. This could also allow for smaller manual pulls to the 'partially frozen' sections, restricting the puzzle from flying out of position.