After upgrading to xf86-video-virtualbox-4.3.24, the vbox linux guest has no 3D acceleration and apps that require it won't run, e.g. gnome3. This is an upstream bug that has already been reported to virtualbox.org (Bug #13933) Reproducible: Always
Unfortunately this same bug still exists in 4.3.26.
Please reopen if this is still a problem on current versions. Upstream's bug report is also asking for feedback if this is still a problem.
This bug report is obsolete. Fixed upstream.