Two basic questions
 

(1) Is there a way to show all actions with a due date of today (and only those actions)?

(2) What does the "Mark Reviewed" toolbar icon do?

[QUOTE=Chris;21007](1) Is there a way to show all actions with a due date of today (and only those actions)?[/QUOTE]

Not quite, but you can come close by grouping by view date (on the View Bar, if you haven't discovered that yet). Once grouped, you can close the groups for date ranges other than today. The easiest way to do that is to select something in the main context view, then Edit --> Select All, then View --> Collapse All, then click the disclosure triangle next to Today.

[QUOTE](2) What does the "Mark Reviewed" toolbar icon do?[/QUOTE]

It marks the selected project, or the project containing the selected action, as having been reviewed. See the Project inspector for the date info. and [URL="http://forums.omnigroup.com/showthread.php?t=4641&highlight=reviews"]this thread[/URL] for more details on how some of us are using reviews. (Note that this is probably power-user territory. I used OF for two months before touching the review functionality.

[QUOTE=curt.clifton;21016]Not quite, but you can come close by grouping by view date (on the View Bar, if you haven't discovered that yet). Once grouped, you can close the groups for date ranges other than today. The easiest way to do that is to select something in the main context view, then Edit --> Select All, then View --> Collapse All, then click the disclosure triangle next to Today.
[/QUOTE]

Ah, I had done that, but only saw "Within the next month" and "None" because I haven't assigned many due dates yet. I (stupidly, perhaps) didn't realize that the absence of other groups (Today, This week, etc) just meant that nothing was due today or this week.

What are all the possible categories here? Is there a "Tomorrow" group, for example? It might be nice if this were somehow exposed in the interface.

[QUOTE]
It marks the selected project, or the project containing the selected action, as having been reviewed. See the Project inspector for the date info. and [URL="http://forums.omnigroup.com/showthread.php?t=4641&highlight=reviews"]this thread[/URL] for more details on how some of us are using reviews. (Note that this is probably power-user territory. I used OF for two months before touching the review functionality.[/QUOTE]

Thanks. I didn't notice that I could group or sort by "Next Review", and I had overlooked the Review section of the project inspector.

[QUOTE=Chris;21036]
What are all the possible categories here? Is there a "Tomorrow" group, for example? It might be nice if this were somehow exposed in the interface.[/QUOTE]

I'm showing:
[LIST][*]Within the last month[*]Within the last week[*]Yesterday[*]Today[*]Tomorrow[*]Within the next week[*]Within the next month[*]None[/LIST]
I do not want the UI to show me the categories that are empty. That seems like noise to me. Do you have a reason why they would be useful, apart from just an initial curiosity about the possibilities?

I don't know that I really want empty categories either, but ...

(a) I think I do want the ability to modify the categories. I could imagine a "By Friday" category or a "This weekend" category.

(b) One of the things I'm struggling with right now is knowing when a category is really empty, and when I've just set the filters (maybe accidentally, or because they're held over in switching from planning to context mode) so that it appears empty. Right now there's no real way to tell the difference between those two things, which makes me not trust what OF is showing me, which is at odds with GTD.