Hannalore: Your example (we're discussing using utalics for internal thought, here) :

Why doesn’t she come in? Melanie busily stirred her coffee. She quickly glanced over to the other two personnel counselors.

So, I'm assuming that this whole chapter of scene is in the viewpoint of Malanie, right? And you do a very smart thing. You put the name Melanie right after the internal though of "Why doesn't she come in." So, your reader know on two counts whose head you are in and that this is internal thought.
1. You're doing the scene or chapter from Melanie's viewpoint anyway.
2. The very next sentence in that same paragraph shows what Melanie is doing and tells us that it is Melanie doing it.

So, your reader knows that it is Melanie's internal thought. You don't need to slam her or him (the reader) with it by putting saying "she though" which you already sensed. But you also don't kneed to put it in italics for the reader to know. Trust me, she does. And she knows its not an outloud comment because there are no quotation marks. She won't have to think about this. She is a reader. She just knows. And you, as a writer are in partnership with your reader, so you need to trust her a bit more.

Additional note: Showing what a character is doing while she is thinking or speaking is very good technique for helping a reader to know where she is. It also helps with the setting and often characterization as well. Beginners often don't know to use this technique.

Now, just to clarify. You CAN use italics for internal though. The question is, do you need to. I heard of one person who used italics when it was the internal thought of a robot and it was often inerspresed with an unspoken exchange of thoughts with a human. The robot's thought-dialogue was in italics. That seems like a really legitimate use of them.

In This Is the Place, I used italics to show when the protagonist was writing in her journal. I would never do that again. I would just transition to the journal better. The readers would have known if I'd transitions from real life to life of the written word better. That was eight years ago and one of the reasons I wrote The Frugal Editor. So that others could avoid learning things the hard way. I was a journalist and publicist. What did I know about fiction techniques when I started creative writing. With apologies to journalists everwhere, not much. (-:

So, What do you think? Are you all going to shoot punctuation marks at me for being such a spoil sport? Now, what about italics used for other reasons. When do we use them, when not? Hint: Most of us use them way too often.

Oh, PS. Yes, Christine Hohlbaum is getting quite well known. She's bee on NPR radio several times and has her own PR firm as well.

Best,
C.

Best,
Carolyn