I’m using On The Agenda to keep the Notes I plan to work or refer to next, easily available - and as a reminder: A glance at OTA gives me an overview of the broad topics I need to tackle, without overwhelming me with the detailed tasks (which will usually be Reminders in those Notes).
However, I use Categories and Projects to groups my work, and generally I focus on one Project or Category over a day. It would be really helpful to just collapse all the Projects and Categories except the one I want to work on, and clear the distraction.
So, the ability to collapse Projects and Categories in OTA by clicking on them would be really helpful. Even more helpful would be a command to ‘Collapse Others’ - analagous to Hide Others in the Mac Finder.