Back in the day, it seemed like GroupBoxes were everywhere. Now, modern RIA kits don't even have them as basic components (Flex / GWT / Silverlight). Is there a reason for the decline in use - are they bad practice for use in an interface?
If you develop for Windows, I recommend that you read about group boxes in Microsoft UX Guide, which can be downloaded from here, starting on page 91. There you will find guidelines on where group boxes are considered right or wrong. (See examples in the PDF.)
- Is there more than one control in the group? If not, use a plain text label instead. A rare exception is to use a group box with a single control to maintain consistency with other group boxes on the same surface.
- Are the controls related? Does showing the relationship add clarity? If not, present the controls separately outside of a group box.
- Are all the controls inside the group? If so, indicate the relationship on the larger surface, such as the parent dialog box or page.
- Can you effectively communicate the relationships without text? If so, consider using graphic elements such as backgrounds or aggregators.
Dunno if they're a bad practice but I'd say they more or less correspond to the HTML
Still necessary to group / categorize options in my opinion in case of large amounts of options.
But, no, I have no idea why exactly GroupBoxes are less used...maybe because they were mainly used in WinForm-based UIs and that these have clearly declined?