Arrows pointing to albums

[J Mark Troyer]

Can someone please explain why some of the arrows in my Lightroom albums are solid and some are semi-solid. I'm sure it's an indicator of missing information. I'm just not sure what information. Thank! 

[Jim Wilde]

Nothing to do with missing information. Quite simply, a folder with a solid arrow indicates that the folder contains sub-folders (click on the solid arrow to reveal the sub-folders). The non-solid arrow means that the folder does not contain any sub-folders, i.e. it's at the bottom of the particular folder hierarchy that it's in.

[J Mark Troyer]

Thank you Jim!