I can confirm I'm recently facing the same issue. Not sure this is a graphics driver issue. Might have happened just after a kernel update.
uname -a shows : Linux ggalibert-Latitude-E4310 3.2.0-58-generic #88-Ubuntu SMP Tue Dec 3 17:37:58 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux Ubuntu 12.04 LTS 64-bit Intel® Core™ i5 CPU M 580 @ 2.67GHz × 4 Intel® Ironlake Mobile -- You received this bug notification because you are a member of DX Packages, which is subscribed to unity in Ubuntu. Matching subscriptions: dx-packages https://bugs.launchpad.net/bugs/1268167 Title: No Autohide Launcher Bar Mouse Reveal on Secondary Monitor Status in Unity: New Status in “unity” package in Ubuntu: New Bug description: Since several updates performed on 1/8/2014, I am no longer able to reveal the launcher bar on my secondary (right) display with the mouse auto-reveal function. Under display settings, both monitors are set to display a launcher bar. Auto reveal works fine with the mouse on the primary (left) monitor. The sticky edge works fine with the secondary (right) monitor, but no auto reveal for the launcher bar. I can bring up the secondary (right) monitor launcher bar with the super key and alt+f1. So far I've reverted to Nvidia 3.04 drivers from 3.19 by purging from terminal and re-installing to no avail, and now back to 3.19 and it's still not working. Ubuntu 12.04.4 LTS 32-bit AMD Athlon 64x2 Dual Core Processor 6000+ Nvidia GT630 PCIe 2GB RAM Any outputs you'd like from me, please let me know. To manage notifications about this bug go to: https://bugs.launchpad.net/unity/+bug/1268167/+subscriptions -- Mailing list: https://launchpad.net/~dx-packages Post to : dx-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~dx-packages More help : https://help.launchpad.net/ListHelp
