I use Kubuntu 14.04 LTS x64 and it seems to use some sort of Adaptive Activation area menu, i.e. it eliminates corner steering by default. This affects all applications I have tried (kickoff start menu, Eclipse, Google Chrome) so it seems to be a system setting.
(Source: E. Tanvir, J. Cullen, P. Irani and A. Cockburn. "AAMU: Adaptive Activation Area Menus for Improving Selection in Cascading Pull-Down Menus." CHI 2008.)
Is there any way to disable Adaptive activation areas in the menu to allow corner steering?