Something else to check about eclipse (if you update to Mars.1) is that with Mars and Mars.1, GTK3 is now the default SWT library. Try export SWT_GTK3=0 before launching your eclipse or RCP program to test with GTK2.
Something else to check about eclipse (if you update to Mars.1) is that with Mars and Mars.1, GTK3 is now the default SWT library. Try export SWT_GTK3=0 before launching your eclipse or RCP program to test with GTK2.