There's no explicit view/review mode, but it is something that we've talked about adding to a future release.
A workaround is to either:
1) Create a copy of the data file and open that in CSEntry. That way, if the data is modified, it doesn't really matter since the modified data was part of the copied file.
2) Add a custom flag to the PFF that indicates that you are in review mode. Then in logic, whenever data might be saved, you check the flag. For example, you might have a custom partial save function:
function CustomPartialSave()
if sysparm("REVIEW_MODE") <> "1" then
savepartial();
endif;
end;
PROC LAST_ENTITY_OF_APPLICATION
// prevent the finalization of the questionnaire in review mode
if sysparm("REVIEW_MODE") = "1" then
stop(0);
endif;