If you upgrade to Ubuntu 9.10 and then eclipse buttons stop work.

 

There is some bug in eclipse regardes to SWT on GTK

 

https://bugs.eclipse.org/bugs/show_bug.cgi?id=287307 this bug is fix in eclipse 3.6 M2

 

There is workaround to set System enviorment in the shell you start eclipse from.

 

export GDK_NATIVE_WINDOWS=1