First of all, many thanks for Helium! Several days before Helium’s release, I discovered the groupBox stylename „light“, which only displays the top line of the groupBox, including its caption. IMHO, this option is great if you have several groupBoxes next to each other or on top if one another…
Thank you for your feedback. We certainly have plans to implement both classic and lightGroupBox styles. I’ve created a GitHub issue for the light style so you can track its status. Unfortunately, I can’t provide a certain deadline. As you can see, GroupBox in Helium has a different appearance, so the light style, by our design, also will have a different appearance than in other themes. Currently, there are some technical problems that prevent us from implementing it.