There is a workaround for Linux users. If you add Terminal=true to the desktop launcher then ROOT session will run in a Terminal window and TBrowser window will stay open.
It is rather useful to run TBrowser in terminal window because you can right-click and dump ROOT objects in the Terminal output. My rootbrowse launcher looks like this:
[Desktop Entry]
Type=Application
Name=ROOT Browser
Comment=Open CERN ROOT files
Icon=gnome-cernroot
Exec=rootbrowse %F
Terminal=true
Categories=Science
Please refer to the freedesktop launcher specification here. This should work in KDE and GNOME desktop environments and derivatives.