OK. I think I found what you are seeing. Does this match what you are doing?

1. Your current sheet is the one you're going to hide in a moment
2. You start placing symbols. This causes CC3+ to automatically (and temporarily) switch to the SYMBOLS sheet
3. You hide the sheet from 1. while you still have a symbol at your cursor
4. You stop placing symbols.

If this is the case, this behavior is by design. Tools that places things on specific sheets need to temporarily switch to this sheet, but to avoid breaking your workflow and ending up confused why you suddenly was on a different sheet, it will switch back to the sheet you were on when you end that command (stop placing symbols, end the drawing tool, etc). The sheet is then made active immediately, but because there isn't an automatic redraw, you just don't see it immediately when it was hidden. So it isn't the redraw that restores it, but it is at the point of the redraw you will notice it, but if you look at the status bar, you'll se that it has become the active sheet already before you to the redraw.

Here's roflo1's entry, the South Gate, now added to the atlas.

This concludes the contest entries, as I've added the ones I've gotten .fcw files for. Next entry will be one of those others in queue.

I've also updated the contest page on the atlas site to include this one.

The weird lines typically happens when you have nodes very close to each other making sharp turns (They're miter joins gone extreme). In many cases, this can be fixed by running the SIMPLIFY command on the polygon. This command automatically deletes nodes that are too close to each other based on the distance you give.

The DELNODEW command will appear in the future.

Great find.

As you point out, they will take a bit of work to get them into CC3+ format since he's presenting them as pages with many symbols on each. But, with the CC0 license, it do mean that it can be done by one person and shared/redistributed legally.

In this case, this is because you have created a map in the very limited CC3 Dungeon style. This is just a small preview of what dungeon styles can do, and can be used to create simple dungeons, but it doesn't include a cave tool, which is why the button can't find one.

I recommend trying another style, such as DD3 dungeon or one of the other dungeon styles available.

I also notice from the file name in the title bar that you have managed to save your file in the CC3+ installation directory under program files. Don't do that, it is a bad place to keep your maps. I recommend creating a folder inside your personal documents directory or similar.