Bug 31395 Child window of Preferences dialog centers between screens
On the Preferences->Java->Code Generation->Names tab, the Edit button opens a dialog that is split between multiple monitors, instead of centering on the main Preference window like the rest of its child windows do.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/NameConventionConfigurationBlock.java
if (val.length() == 0) {
					if (prefix) {
						return new StatusInfo(IStatus.ERROR, PreferencesMessages.getString("NameConventionConfigurationBlock.error.emptyprefix")); 
					} else {
						return new StatusInfo(IStatus.ERROR, PreferencesMessages.getString("NameConventionConfigurationBlock.error.emptysuffix")); 
					}							
				}
				String name= prefix ? val + "x" : "x" + val; 
				IStatus status= JavaConventions.validateFieldName(name);
				if (status.matches(IStatus.ERROR)) {
					if (prefix) {
						return new StatusInfo(IStatus.ERROR, PreferencesMessages.getFormattedString("NameConventionConfigurationBlock.error.invalidprefix", val)); 
					} else {
						return new StatusInfo(IStatus.ERROR, PreferencesMessages.getFormattedString("NameConventionConfigurationBlock.error.invalidsuffix", val)); 
					}
				}
			}
			return new StatusInfo();
		}		
	
		/*
		 * @see org.eclipse.jface.window.Window#configureShell(Shell)
		 */
		protected void configureShell(Shell newShell) {
			super.configureShell(newShell);
			
		}
	}	
	
	private static class NameConventionLabelProvider extends LabelProvider implements ITableLabelProvider {