The laz_fpspreadsheet package (which contains the basic spreadsheet code) and the laz_fpspreadsheet_visual package (which contains the runtime code of the visual spreadsheet controls) are runtime packages, this means that they cannot be "installed"into the IDE, they are only compiled, but the IDE knows where the compiled units are found.
Only the laz_fpspreadsheet_visual_dsgn package is a designtime package and MUST be installed. It is responsible for the palette icons.
When you click one of these spreadsheet controls onto the form only the runtime package is added to the project requirements since the designtime code is only needed by the IDE, but not by your program.