Which version of tools are you using? If you're using the v19 set of tools, you want to use the Scrollable Frames overlay. If you're using v18 or earlier, you want to use Pan & Zoom > Pan Only. There are no known issues with scrollable frames in v19 -- it should work as described.
I have just updated to v19 and will test again. Thanks for your reply!
I have tested again.
In a short article (4 pages) everything works just fine in horizontal and vertical layout.
However in a long article (41 pages) the vertical scrolling of text in the horizontal layout simply doesn't work except a one exception. I have checked all the settings - they are identical.
The strange thing is that if I preview the horizontal layout in the ADOBE Content Viewer all the scrolling works just fine, but as soon as I add the complete article consisting of horizontal and vertical layout to the folio things stop to work.
This is really frustrating. Maybe it's necessary to re-think the layout and avoid scrollable content since it so unreliable.
Right now I have no idea how get this to work.
The tools I use are: InDesign CS5.5 on OSX 10.6.8, FolioPanel-CS55-12_1_3, FolioProducerTools-CS55-1-9-1
Any help would be apprechiated.