I got an EX-word a couple months ago. I know all the arguments about it being a waste of money, so please spare me those arguments, please.

My question is about the notation of the dictionary entries themselves. For example, this is for ろくでなし:

【▿陸でなし・×碌でなし】
①のらくらしていて役に立たない者。
◆「碌」は当て字

As you can see, there's a little triangle before 陸でなし, and a little 'x' before 碌でなし.
These symbols appear in countless other entries, but for the life of me I can't figure out what they mean. I've searched Google, but I don't think anyone else has had this problem, or if they have, they haven't asked about it.
So here I am. Does anyone know what the 'x' and/or triangle means? I'm almost certain it has to do with whether the kanji used in each version are common or not, but, like I said, I haven't been able to find out for sure.

Any and all help is appreciated. Thank you!

This is from Daijisen, right?
It matches my EPWING Daijisen's definition, so I'll assume it is.

Read here, especially the first line.
Other dictionaries are pretty similar. Generally little shapes in the headings show that it contains non-Jouyou kanji or kanji readings, like you guessed ^-^

It's probably explained in the manual.