Holy shit, I have installed modific too. And I'd never suspect it of such sabotage. Thanks, Daniel.

I'd tried turning off save_on_focus_lost right after this strange behavior revealed itself the first time but with no effect. Files tend to be saved when view gains focus, not on focus lost.

Combining it with hot_exit=false does not help too.

Never mind, being highly annoying at first day of usage this drawback became almost unobtrusive in a week. I'm already used to click any other sidebar item or tab right after deletion to eliminate it =)