Through the cog in the top right corner of the post. Note that you can only delete a comment, not a topic. The latter is due to how the developers wrote the forum software, since deleting a topic would also mean deleting all the comments of the topics (which probably don't belong to the poster of the topic), so they simply did not allow users to delete topics (even if there are no comments yet)

Symbols keep their layer when defined, and the entities should normally be put on the SYMBOL DEFINITION layer before you define them, this won't happen automatically. As for the Common sheet, that doesn't really matter that much, since sheet information is lost when defining the symbols, but having all entities on the same sheet is a good way of seeing that things look right, otherwise the actual entity order in the finished symbol may not be as you percive it since sheet ordering trumps entity ordering. Using Common is a good practice, because Common isn't a sheet at all, it is just all the entities that doesn't actually have a sheet, which is exactly the situation for a symbol definition.

For the catalog, yes. A good way to build a custom catalog wich includes existing symbols is to first make a catalog with your symbols, using save as catalog from the symbol manager. Then, open this new catalog up as a map (as opposed to in the symbol catalog window), and then open up the catalog with the symbols you want to insert in the symbol catalog window, clicking on each symbol once to import it into your own catalog. Then simply save it (using the normal save button this time, no need to to the symbol manager route every time).

Well, I guess that too will serve to keep a map dry. Well, unless you try to use it as a flotation device that is....

Oh, and to save you a click on the explode button, you can configure a symbol to automatically explode on placement, although this option is not compatible with the multi-sheet option for symbols.

Mennidas' linage is now in the atlas. Thanks for the contribution Quenten.

Turn off snap (lower right corner) when working, this allows you to place nodes right outside the map border, and let the functionality that restricts it to the map border kick in.

With snap on, you are basically just placing nodes at the edge, but not over it, so it treats it as a regular corner. Note that you can achieve this with snap on too, but you need to move your cursor much farther out from the edge of the map to hit the snap points on the outside and not those at the border itself.

Yea, this particular article was written with the intent to hide things that are "outside" the structure.

When it comes to your house, that's a very tricky thing if you let the players have access to the entire map, as that clearly allows them a different view than a person there would have, and instantly reveals things like too-thick walls or suspicious corner. I would be tempted to give the players a modified version of the floor-plan, where the rooms are slightly larger, maybe the house slightly narrower to hide such thick walls. Only if they actually start measuring things should they be given the true map so they can see that there is something wrong here....

Of course, some players may call foul on such an approach, feeling mislead. And it also means preparing two maps instead of simply hiding something.

For reasons like this, I usually never let the players see the entire dungeon. I practice hiding everything they can't currently see. (Using MapTool hooked up to a projector)

Maybe you could write a blog article about the process and your thought patterns some time?

There isn't a setting for a default save location, but it should be remembering the last folder used.

For a workaround, you can also use Windows' only features, such as pinning a folder to quick access or making a library, since these are easily accessible from the save as dialog.

Looks like your current map is in the basic CC3 dungeon style. That style doesn't have additional catalogs, as it is just a vary simple preview style for dungeons. All symbols are in the symbol catalog being loaded with the map, the one currently in your symbol catalog window.