Page scrollable when ionic popup overflows

I want to create a page scrollable when a ionic popup overflows it, instead of making the popup itself scrollable. The perfect example would be the register popup on the airbnb website (click register with an email address, cf. screenshot)

However when my ionic popup opens, the page is not scrollable and the popup overflows (cf jsfiddle).

I tried to add a scroll=’true’ to the <ion-content> tag and to call $ionicScrollDelegate.$getByHandle(‘mainScroll’).resize(); but it did not work.