why this one (if @is-mobile)... will rerende and this one (if (and @signed-in? (not @is-mobile)) won't? Is it too nested?

@poiga Nesting isn’t the problem. As long as you dereference an atom during the render function, that will work. There a number of other problems that might be happening. Check out this and see if it helps or post more code and I’ll try to help. https://github.com/reagent-project/reagent/blob/master/docs/FAQ/ComponentNotRerendering.md