Attached patch fixes the problem.
One way to avoid the splitting of datetime values into two columns is to use ISO-8601 format for copy/paste. See the attached files for an example.
I have no problem in reading your 'Exercise2.sciprj' file with the linux version of SciDAVis (2.4.0 in Fedora). But I also couldn't open the file with the windows version of SciDAVis. Can you please test if you can open the attached file 'Exercise2-corrected.sciprj'? If it works, then to get around this bug you should avoid saving a project with minimized Table, Graph, or Matrix windows.
You should not use 'e' or 'pi' as a parameter name as they are defined as constants. See SciDAVis manual Miquel
See liborigin-devel mail list. As for the error when importing a .opj file, you can try if opj2dat from liborigin can read that file. If not, post a message to liborigin-devel attaching the problematic file.
Since release 1.23.1, copy/pasted data in a column is treated as numeric IF and ONLY IF all the pasted data is numeric. Can you please share a version 1.21 "*.sciprj" file BEFORE pasting the excel data and the corresponding version 2.3.0 "*.sciprj" obtained AFTER pasting?
I cannot reproduce this bug in linux. I guess it is a Windows only problem. As a work around you can use version 1.26
You can get libqwt5-qt5 .deb file from https://software.opensuse.org//download.html?project=home%3Ahpcoder1&package=libqwt5-qt5 or compile it yourself from https://github.com/gbm19/qwt5-qt5