Using the Undo Macro command undoes any curve fits that were applied. This information is not recoverable and the Redo command will not bring it back. This is a design decision that was made back in v1.1 of KaleidaGraph. Otherwise, there is a high probability of a System crash.
KaleidaGraph is a thoughtfully designed graphing and data analysis application for research scientists, as well as for those in business and engineering fields. It produces publication-quality graphs, and easily converts the most complex data into a functional display.