The current ebuild of FreeCAD 0.11 rev 3729 produces a menu item under "Graphics" in Gnome. This menu item runs the command "FreeCAD", but the program does not come up. If the same command is issued from a terminal window, the program comes up normally. System is (mostly) stable x86 Pentium 4. Bug is duplicated on a second, similar system.
Can't reproduce this, sorry. The same menu entry (i.e. desktop file) works fine under KDE. Please check if you get an error message somewhere (e.g. .xsession-errors ?)
Re-checking this three months after the original report, I can't duplicate it either. The menu now works as expected. Since I update my system every week, this is probably not surprising. Thanks for your efforts.