Hi,
You can use below code to open sized window using html snippet.
<a href="https://yoursite.com" target="_blank" onClick="window.open('https://yoursite.com','pagename','resizable,height=600,width=800'); return false;">New Page</a>
Thanks.
You can try opening the Mendix page in an iFrame from your application (this should allow you to define the iFrame size).
Example
<iframe id="inlineFrameExample"
title="Inline Frame Example"
width="300"
height="200"
src="https://www.something.com’
</iframe>
I’m not sure I got the point.
Do you want to open the current page in Mendix in a different window with a predefined size?
Is it a kind of popup?