Save a GUIDE UIAppend New Callbacks to an Existing GUIDE Code File
If you save a GUIDE UI to an existing file, GUIDE displays a dialog box that asks you if
you want to replace the existing FIG-file. If you click Yes, GUIDE displays a dialog that
asks if you want to replace the existing code file or append to it. The most common choice
is Replace.
If you choose Append, GUIDE adds callbacks to the existing code file for components in
the current layout that are not present within it. Before you append the new components,
ensure that their Tag properties do not duplicate Tag values that appear in callback
function names in the existing code file.