I’ve seen something similar with the iPhone app. There have been a few occasions when I start the app, it seems to behave normally for a few seconds, and then it becomes unresponsive or a translucent fray rectangle appears, with the loading/cog symbol appearing in the middle, but it then stays that way. I’m presuming it is caused by a syncing issue. I’ve tried using both 3G and WiFi, in case there was a network problem that was causing syncing difficulties.
I tried closing the app and restarting it, but ran into the same problems. Sometimes the app crashed, dumping me back to the home screen of iOS, but the app would still be running. Whether I went straight back into the app or first tried closing the app (before loading it again), the result would be the same. Like you, Anna, I found restarting my phone seemed to solve the problem!
Fortunately, it’s been an infrequent bug overall, but it did bother me quite a lot because it made the app unusable unless I restarted my phone. There was one day when OmniFocus was locking up frequently and I had to stop using it. I’m usually very diligent about closing apps that I am not using. I am now leaving the OmniFocus app running constantly in the background, never closing it, and the problem has not reappeared since. So it could be a coincidence, but I wonder if that is an alternative solution to restarting your phone. If I learn anything new, I’ll be sure to post it.
For the OmniFocus team, I’ll provide technical details in case they help to track down the cause:
iPhone model: 4s
iOS version: 8.1.3
Network usage at the time: Either 3G or WiFi. Internet access was fine at the time.
What I was doing prior to the issue: I had just loaded the app. Accessing the Inbox, Projects, etc. or manually initialising a sync would reliably bring on the problem, but checking Perspectives seemed safe once or twice.
Sync: With Omni Sync Server
Reminders Capture used: Yes, although I rarely use Reminders now (so yes only in theory?)
Calendar alarms: Yes
OmniFocus in Today list: Yes
Custom keyboard: No
If any other information would be useful, please let me know. I think OmniFocus is a useful app and I’m glad to help in any way I can.