FYI bug confirmed by Sparx and being investigated.
Behaviour is influenced by the choice of Visual Style - with some visual styles the controls work find but wth others they exhibit the behaviour as described. For anyone that is interested here are the styles:
- ‘broken’ behaviour in “Visual Studio 2013”, “Visual Studio 2012”, “Carbon”, “Microsoft Office 2016”, “Microsoft Office 2013”, “Microsoft Office 2010”, “Microsoft Office 2007”
- Scrollbar works in “Visual Studio 2010”, “Visual Studio 2008”, “Visual Studio 2005”, “Microsoft Office 2003”, “Microsoft Office XP”, “Microsoft Office 2000”