One of the top reported Microsoft Connect issues with Visual Studio 2010 has been an issue where context menus scroll even when there is sufficient screen real estate to show the menu in its entirely (with no scrolling required). The VS and WPF teams issued public hotfixes "We've been looking into the widely-reported problem with VS 2010 where context menus contain scrollbars even when there is sufficient screen real estate to show the menu without one. We're pleased to announce that there're patches available for VS and Windows Presentation Foundation that fix this problem."
You'll need to install both patches to fix this issue:
- VS 2010 patch: KB2345133
- WPF 4.0 patch: KB2413613
- X86: NDP40-KB2413613-x86.exe.
- X64: NDP40-KB2413613-x64.exe.