We don't officially support it, so it's not documented. But you can still do it.
In the UI Editor, select on Edit>>Edit Custom Controls, then scroll to the control you want to change, click on the Edit Name and prepend it with the name of the sub-menu you want it to appear under. For example, if the control is named "My Custom Control", change the name to "My Group/My Custom Control".
Then, exit and restart CVI. When it reappears, it will show the custom control under a submenu called "My Group".
One caveat is that you won't be able to change it in the dialog after you name it the first time. But you can still change it if you need to. There is a file in the bin folder of your CVI installation called customCtrls.tui. It's just a text file that you can edit (make sure you exit CVI first). Find the name of your control (it should be in a tag that looks like this: ATTR_CUSTOM_NAME="My Group/My Custom Control".) Simply change the name here. That will also work.
Luis
NI
