Bug 123786 Following bug 109980, the compliance 6.0 should be added to the compiler's compliance list.
If the JRE/JDK used is a 1.6/6.0 VM, then the compliance 6.0 should be available. Compliance 1.6 implies source level 1.6 and target level 1.6.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/ComplianceConfigurationBlock.java
return complianceComposite;
	}
	
	public void enablePreferenceContent(boolean enable) {
		if (fControlsComposite != null && !fControlsComposite.isDisposed()) {
			if (enable) {
				if (fBlockEnableState != null) {
					fBlockEnableState.restore();
					fBlockEnableState= null;
				}
			} else {
				if (fBlockEnableState == null) {
					fBlockEnableState= ControlEnableState.disable(fControlsComposite);
				}
			}
		}
	}
	
	private Composite createComplianceTabContent(Composite folder) {
		String[] values345= new String[] { VERSION_1_3, VERSION_1_4, VERSION_1_5 };
		String[] values345Labels= new String[] {
			PreferencesMessages.ComplianceConfigurationBlock_version13,  
			PreferencesMessages.ComplianceConfigurationBlock_version14, 
			PreferencesMessages.ComplianceConfigurationBlock_version15
		};
		final ScrolledPageContent sc1 = new ScrolledPageContent(folder);
		Composite composite= sc1.getBody();
		GridLayout layout= new GridLayout();
		layout.marginHeight= 0;
		layout.marginWidth= 0;