MESSAGEBOX("Test-" + CHR(0) + "--second part")It only shows "Test-". That's a limitation of Windows, by the way, not VFP. If you use a DECLARE DLL to declare the unicode version, you can use the longer form:
DECLARE INTEGER MessageBoxW IN WIN32API INTEGER hWnd, STRING lpText, STRING lpCaption, INTEGER uType messageboxw(0, STRCONV("Unicode Text",12), STRCONV("Caption",12), 0)