I’m currently facing a similar issue, but I’m hoping (from looking at your design) that yours might be a little easier of a solve.
I’m assuming your RG is set to vertical scrolling, correct? If so, vertical scrolling is not responsive, which means it does not expand as the page expands. It is locked to the height you set it to previously. You could try adding the following css to the HTML Header section in the options of the page.
<style>
#idofRG {
height: 100vh !important; /* Force RG to height of floating group. Might need to be 90vh, just play with it*/
bottom: 100px !important; /*this is to account for your text input area. You will likely need to change this number. You might also need to try switching it to "top: 100px" as reversing your RG may make the top into the bottom.*/
}
</style>
In theory, this will force the RG to full height of the floating group, but then also move it 100px off the bottom of the floating group to leave space for your text input area.
I’m currently facing this in a text messaging context. The problem I ran into with this solution is that because I have so many items being shown and hidden in my RG (images, text, message info, etc) and the message lengths can be so different, no matter how many cells I did or didn’t add to the VS RG it would not load correctly. So basically I can’t use vertical scrolling, only full list, which causes other headaches I won’t scare you with lol.
If you can get the RG to dynamically change height based on VH then that will be the way to go for sure.