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.

No, hitting load will load ALL the slots at once from what's in the file you pick. The saved files are a collection of filters, loading loads the entire collection from each file, not just a single item to put into a single slot.

To make a custom setup, you'll just need to type the filters you want into each slot and then save it. This will save a file with the complete set of all slots you have defined, and when you load it, it will load all the slots from that file.

If it were to load just a single slot at a time, it would be impossible to make a file containing many filters at once (which is precisely what you're attempting to make), because you couldn't load it again.

When you load a master filter file, it loads all those slots, not just the first one, you don't load files into slots. Almost all of the existing master filters are using the first slot for the style, because the first one is the one activated by default.

But you can make your own file by filling out the different slots, and then save it as a new master filter file. When you load that file, it will contain he slots as you saved them, and the symbol style toggle button will toggle between those in the list.

You can use the SYMDELNEAR command to do this.

Symbol filters are loaded in the OnOpenMacro map note. Should be a line saying SYMICONFLOAD CA163 in there.

You can also manually load them by right clicking :CC2SYMPATH: and picking Master Filter Settings, hit Load in the dialog and load the CA163 setting. (While in the dialog, you can then also check that the CA163 is in the Filter 1 position after loading, and that it is the selected filter)