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
};
		ColumnLayoutData[] data= new ColumnLayoutData[] {
			new ColumnWeightData(3),
			new ColumnWeightData(2),
			new ColumnWeightData(2)
		};
		
		fNameConventionList.setTableColumns(new ListDialogField.ColumnsDescription(data, columnsHeaders, true));
		unpackEntries();
		if (fNameConventionList.getSize() > 0) {
			fNameConventionList.selectFirstElement();
		} else {
			fNameConventionList.enableButton(0, false);
		}
	}
	
	protected String[] getAllKeys() {
		return new String[] {
			PREF_FIELD_PREFIXES, PREF_FIELD_SUFFIXES, PREF_STATIC_FIELD_PREFIXES, PREF_STATIC_FIELD_SUFFIXES,
			PREF_ARGUMENT_PREFIXES, PREF_ARGUMENT_SUFFIXES, PREF_LOCAL_PREFIXES, PREF_LOCAL_SUFFIXES
		};	
	}	
	protected Control createContents(Composite parent) {
		PixelConverter converter= new PixelConverter(parent);
		
		GridLayout layout= new GridLayout();
		layout.numColumns= 2;
		Composite composite= new Composite(parent, SWT.NONE);
		composite.setLayout(layout);
		int heightHint= converter.convertHeightInCharsToPixels(5);