I reinstalled Ubuntu Touch and the problems persist. I no longer have Linphone of course since the fresh install.
When I select the delete button in Gallery or picture folder in Files, a popup appears to confirm deletion. However, the red "ok" button never functions. The grey "cancel" button works but not "ok".
I also can't delete apps or a chat in the Teleports app.
Is this a problem of the Ubuntu Touch operating system or a setting that I haven't enabled on the OnePlus One to allow deletion?