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/OptionsConfigurationBlock.java
if (widthHint != 0) {
			data.widthHint= widthHint;
		}
		data.horizontalIndent= indent;
		textBox.setLayoutData(data);
		fTextBoxes.add(textBox);
		return textBox;
	}	
	protected SelectionListener getSelectionListener() {
		if (fSelectionListener == null) {
			fSelectionListener= new SelectionListener() {
				public void widgetDefaultSelected(SelectionEvent e) {}
	
				public void widgetSelected(SelectionEvent e) {
					controlChanged(e.widget);
				}
			};
		}
		return fSelectionListener;
	}
	
	protected ModifyListener getTextModifyListener() {
		if (fTextModifyListener == null) {
			fTextModifyListener= new ModifyListener() {
				public void modifyText(ModifyEvent e) {
					textChanged((Text) e.widget);
				}
			};
		}
		return fTextModifyListener;