My solution to this has been an 'Anywhere' context, for things that I can really do anywhere (e.g., 'Spend 10 minutes thinking about X').Д«ut I find there are very few things I can really do in multiple contexts. I frequently run into this situation, where I have a task that could be taken care of in any of several contexts, and I don't know which one of those contexts will come up next for me in my hectic schedule. So even though Buy Tickets might be in the Phone context, it would show in my list and I could choose to do it using the web instead. I use cmd-clicks in context view to select all of them. For example, currently I can choose actions from my home:office context, any of my computer contexts, my phone context, or my briefcase context. I seldom am in a single context at a time. Personally, I would use the third option. (This is really like bongoman's suggestion, but assumes that picking the context takes less than 2 minutes.) Enter the action twice with two different contexts.Create a new context for 'Phone or On-line'.There are a few ways to deal with cases like Buy Tickets now. There has been extensive discussion on the forums about adding multiple context support, or some notion of tags or labels. If I'm afraid to reach a goal, I can always keep dividing the steps between me and the goal into more and more next actions.) For an 'over-organizer' like me, too many next actions can be as big a roadblock as not identifying the real next action.ДЄs to the original question, currently you cannot assign multiple contexts. (It's really Zeno's dichotomy paradox in action. ? I've sometimes fallen into the trap of procrastinating by always putting a next action in the way. Not to be facetious, but before you 'decide where to buy tickets', shouldn't you research relative service charges and calculate the relative cost of phone minutes vs. Entering a 'decide where to buy tickets' action seems like 'slicing it too thin' to me. Then when that decision is made, you can add a new task 'buy tickets' to OmniFocus in either the calls or online contexts (or your equivalents thereof). I think David Allen would say that in this case the next action is to actually decide where to buy the tickets - that is the next step required to move the ticket-buying project forward.

Omnifocus multiple contexts