When a project is Rebuilded,
with "Recompile All Files" checked,
it don't recompile le prg's files.

Another test is this:

CLEAR
projectName = FORCEPATH("TESTPROJECT",SYS(2023))
programName = FORCEPATH("TestProgram.prg",SYS(2023))
CREATE PROJECT (projectName)  NOWAIT NOSHOW
STRTOFILE("RETURN",programName)
_VFP.ActiveProject.Files.Add(programName)
? "prg is added",_VFP.ActiveProject.Files.Item(1).Name
? "exists fxp before BUILD",FILE(FORCEEXT(programName,"fxp"))
BUILD PROJECT (projectName)  RECOMPILE
? "exists fxp After BUILD",FILE(FORCEEXT(programName,"fxp"))
COMPILE (programName)
? "exists fxp After COMPILE",FILE(FORCEEXT(programName,"fxp"))
_VFP.ActiveProject.Close
ERASE (FORCEEXT(projectName,"*"))
ERASE (FORCEEXT(programName,"*"))

This is much annoying one because BUILD is used when it comes changed a value in .h files,
as an example before compiling the application.

Fabio