Writing slices for your modules is considered advanced PaPCo. This should be attempted only once the general system is well understood.
The basic idea here is to provide extra functionality for the mouse. PaPCo provides all the required routines which will return from the mouse position the panel, the corresponding x- and y-coordinates in that panel, and to hand over this information to a user-written routine. What the user does with this information is up to him/her. Normally, this information is used to re-plot data at that time in a different form, in a separate window. Applications of this may range from simply returning the data values at the mouse position, to calling up a level-zero analysis tool for that time - e.g. for HYDRA, pointing the mouse to a plot of moments data can call up the corresponding level-zero tool to give detailed distribution functions at that time. Or to give POLAR aurora images at that time. Or anything else the user decides.
PaPCo provides some default slices which either work as they are or need a simple user-written interface routine. On top of that the user can configure PaPCo with completely self-written mouse functions.