I wonder if custom made Workspaces might have something to do with it.
I don't think it is anything to do with this. I have tried it on custom workspaces and on a new unsaved workspace and both have the same issue.
Personally I think it is to do with how many rows of library are displayed at the time in comparison to how may rows there are displayed in the texts.
So if there are 20 rows showing in the library then you expand the text which now shows say 60 rows then you press the less button the library shifts up by 40 rows which makes it 'disappear' beyond to top of the library pane.
If the library has more rows showing than the 60 then when it shifts up it does not disappear.
Factored into this is probably the size of the screen because I can get it to display some rows or none at all depending on exactly what position the 'less' button is on the screen when I press it. So if it press it when it is near the top of the screen the library disappears but if I press it when it is near the bottom of the screen some of the library is still available to view.
Edited by Steve King, 15 July 2013 - 12:59 PM.
Steve King Running Accordance 11.0.5 on:
Mac 10.9.5 (Mavericks), mid-2010 Macbook Pro, 4Gb RAM
IOS 8 (iPad 2 and iPhone 6)