Iframe load issue

Hi,

I have an issue with iframe load. I’m using AP resize in order to change the app height, it gets changed but i have this up and down movement. So basically iframe has 150px in initial render and than i resize it to 50px, which causes this movement. Is there a way to prevent it? To have app height at certain px from the very beginning? (‘Example’ is where app should be). See the video below:

screen-capture (2)