@arlo(View Post) The top box is the property you want to set (eg. type/ctype/tmp). The bottom box is the value. Currently the type/ctype are done on the element numbers, not names. Element numbers can be found in the TPT source, in powder.h
The PROP tool is used to edit the particles' values such as type(what kind of particle it is), life(a special number used in timing and sorts), ctype(an element inside an element, like clone's cloning element), temp(a number indicating the temperature) and tmp(another life-type number) The console was before used to edit these variables through the command !set <what to set> <element/particle id> <value> but now you can do it with a tool. For example, FIRE's life defines how long it has got to "live" in the world. Water's LIFE is used for sparks. With the prop tool you can set, for example. clone's cloning elements or DLAY's delay or even the amount of expansion DEUT will do. TL;DR: Make DEUT go boom with it.