Is it ok to ask a potential PhD advisor for more information about their future grants? Is there an etiquette when asking Potential Advisors about their future projects?

The reason I ask this is because a Potential Advisor informed me of a future grant that she is applying for, which would have research a topic I am fairly interested in. The advisor gave me a general outline, but she left out some important details that are important to me; my fear is that the advisor will think I am trying to steal the grant idea. Perhaps I am making too much of this?
I think you can certainly ask (nicely) for some more details about her ideas and the research she proposed as part of the grant. Especially so if this is going to be something you end up working on, or close to your own projects. You are, after all, possibly going to work for her! I don't think she will think anything else than you having interest in her research, which is quite positive.

However, don't ask for the grant proposal (i.e. the written text) itself, as it could be seen as assuming. Ask the questions you have, and let her decide if she wants to reply or simply give you the document to read.