I agree that the command design pattern is the way to go: get each action available in Viking and convert it to a command. I believe it would be possible to have perfectly working versions of Viking with parts of it's actions as commands and the rest as they are now. If choosen carefully the first actions to be converted, there would be a usable and and useful undo feature way before everything being converted.
Windows Start Menu
Implemented on commit 515bc7a Will be available at next release. Thanks for your report.
saved data in th2 files
No software should care about this difference. If you find some software where this difference actually produces some kind of change, please let me know. Thanks for the report.
Fixed the position change of the image file with commit e7687e0 Can you send me the XVI file also so I can test/implement XVI image reading?