Here is what @Jici is talking about. I am showing you images of the new editor and the old editor just in case. You can either ‘detach’ the style and then it will be available for you to edit the condition, or you can ‘edit’ the style so you can modify it everywhere you have that style attached. Hope that helps.
That “when” condition comes from the element’s style. You can’t edit it directly on the element. Go to the Styles tab, find the style applied to your Group Buttons, and either edit or remove the default condition there. After that, you’ll be able to set your own show/hide rules for the page width ≥ 992.