After upgrading Debian Wheezy to Jessie, I experience some random unhiding behaviour of the bottom panel. It does not appear - as before - by moving the mouse into lower right corner. It seems it is showing up, when you move the mouse in the middle of the bottom... but only in 1 out of 15 cases...

  * How is the right way to unhide (is ticking enough or does keeping the mouse there for a few seconds help ... and where)?

  * Are there ways to change the behaviour?

Current Gnome version is 3.12