For about my first week with MailMate I would occasionally
"lose" my inbox, or rather, it would seem to be emptied out or
replaced with nonsense. I eventually figured out that when I
double-clicked on something in the list a search was done for that
item. The only visual confirmation of that was that the back arrow
came alive and there was a "Subject is" line above the list.
Now that I know what's going on I don't mind, and I love the
search features, and I like it being so fast and instant. My mom
would never figure this out. Of course, my mom is not the market
for MailMate, but I think that there a lot of relatively geeky
users who like me would be confused at first, and some subset of
them may dump the program at that point, thinking that it's just
glitchy or buggy.
So from an interface standpoint I think something should
eventually be done about it. For instance, a dialog could be thrown
up saying "Search for subject = _____? [Cancel] [OK]," perhaps with
a few more refinements or options for the search, or the
single-line "Subject is" could be expanded a few lines with options
and more detail and a "Return to Inbox" link, so as to be more
obvious. Or there are probably better solutions. Maybe this should
wait until the next Indiegogo round to raise money to retain a UI
and design consultant.