A few months back (seems like 3 years ago!) someone posted about same issue. I showed a quick demo of how this can work. There is a known bug affecting how widgets get moved when they are in groups.
This might be what is going on with your issue? If so, double check you have the latest release version of RP9–I know they have made some fixes for groups recently. If that isn’t it, Try using a dynamic panel instead of a group (just select your group, right-click, choose Create Dynamic Panel, then click into that dynamic panel, cut the interaction code from the group, if you have any, and paste it to the dynamic panel. If you have interactions on other widgets or page that affects the group, you’d need to update those to point to the dynamic panel.
I haven’t tried this library yet, but perhaps the text field component in this Material Design library has this effect built already: