Right now, Sokoban 3 is unable to test levels while also registering the completion of the level and enabling you to save the score and solution gotten for the level when solving it in the OwnLevels level.
Currently, the only way around this is the copy it to the levels folder and solve it there.
However, when doing this, when you go to make additional levels and copy the level file to the levels folder again, it invalidates all the older levels that you solve and makes it impossible for you to upload scores for the levels without completely removing all scores from your database.
What I suggest is that there is either a separate database for level collections not found in the level sets downloaded from the site, or for there to be an ability to solve levels in the OwnLevels collections, while also allowing for the completion and saving of scores and solutions of these levels in the Own Levels folder, without having any impact on the Level folder database.
While some people might say, just create all the levels you want to for that set and THEN go through and copy to levels folder and solve them, for a prolific level creator, that isn't really the ideal solution because you need to test every level, and sometimes, after you solve a level, you want to tweak the level to make it more difficult, etc. etc.
Thanks in advance!