Navigator pane not showing all folders

The issue I am having is the navigator pane does not allow me to scroll down to the end of the folder structure.

The last fully visible folder in the list is "2017_03_04" the next folder is only half visible with many more folders below.

I'm convinced there's nothing wrong with the path settings, clicking on "go to folder in library" takes me to the half visible folder in the navigator pane, it doesn't take me to the actual folder.

In terms of file/folder location, all pics are stored on a NAS, no duplicate files anywhere else.

In terms of folder structure, there is top level folder, with 1400+ sub folders.

One of these folders is named "album" which contains two sub folders.

One sub folders contains 1000+ subfolders of which 218 folders are visible in the navigator pane.

I want to be able to see the remaining 800 odd folders in LR.

Any tips please.