I’m not sure what the feature is but i’ve attached an image. Our developer said they enabled it in Dev Mode (not as a plugin) and now the lines show both in and out of dev mode all over the designed screen. It does not let me select and delete them, only drag them around. Please help

Edit: 
- Deleting the Frame gets rid of them
- Copy / Pasting the frame brings them back 
trying to avoid having to recreate all the frames it sits on top of. They don’t show up in the layers of the frame.