Thank you so much for offering to help. I have burned so much time going backwards and forwards through the online docs trying to find answers. I managed to solve this one with <script data-options="resize:true" src="https://connect-cdn.atl-paas.net/all.js" crossorigin="anonymous"></script>
I previously had sizetoParent
I now have a new challenge for which I would welcome your help, that is opening a new dialog2 from within a webpanel. Instead of taking over the whole browser window, it just appears in the context of the webpanel, is there a flag or trick I need to use?