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
protected static class ControlData {
		private String fKey;
		private String[] fValues;
		
		public ControlData(String key, String[] values) {
			fKey= key;
			fValues= values;
		}
		
		public String getKey() {
			return fKey;
		}
		
		public String getValue(boolean selection) {
			int index= selection ? 0 : 1;
			return fValues[index];
		}
		
		public String getValue(int index) {
			return fValues[index];
		}		
		
		public int getSelection(String value) {
			for (int i= 0; i < fValues.length; i++) {
				if (value.equals(fValues[i])) {
					return i;
				}
			}
			throw new IllegalArgumentException();