Comment 16 for bug 876299

This bug is fixed in the geda-gaf package 1.8.1, which is not in the standard ubuntu-repositories of Ubuntu 12.04 (as you said, the repository-version for Ubuntu 12.04 is 1.6.2).
If you like to use a gschem version without this bug, please donload the latest version (stable) from http://wiki.geda-project.org/geda:download or compile the latest sources from git (see http://wiki.geda-project.org/geda:developer for instructions)