For me, this bug does not occur anymore on Gutsy Gibbon (7.10).
I tested this on two different computers, equipped with two identical RaLink RT2500 802.11g PCI wireless cards. I installed Gutsy Gibbon freshly on one of these machines, while I upgraded the other one from Feisty Fawn (7.04). Changing the essid works now on both machines under KDE as well as GNOME via the Network Manager applet.
For me, this bug does not occur anymore on Gutsy Gibbon (7.10).
I tested this on two different computers, equipped with two identical RaLink RT2500 802.11g PCI wireless cards. I installed Gutsy Gibbon freshly on one of these machines, while I upgraded the other one from Feisty Fawn (7.04). Changing the essid works now on both machines under KDE as well as GNOME via the Network Manager applet.