Translations:KDevelop4/Manual/Working with source code/29/en
It shows you that the corresponding working set contains two files and their corresponding project names: Makefile and changes.h. Clicking will close and save the current working set (which as shown here has the files tria.h and tria.cc open) and instead open the selected working set. You can also permanently delete a working set, which removes it from the set of saved working sets.