I can't reproduce this on Solaris 10 x86 32bits (installed on VMware). My GTK version is 2.4.9. You can see attached the reproducing video. I added the feature label, then remove the feature label several times. Eiffel Studio works fine.

Attached is a 7 zip compressed format. I can't use zip format since the compressed format will be very big (15M). You can download 7 zip here: http://www.7-zip.org/ I don't know whether 7 zip works fine on Unix systems. Sorry.

The video is AVI format.