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/CompilerConfigurationBlock.java
String[] abortIgnoreValues= new String[] { ABORT, IGNORE };
		String[] cleanIgnoreValues= new String[] { CLEAN, IGNORE };
		
		String[] errorWarning= new String[] { ERROR, WARNING };
		
		String[] errorWarningLabels= new String[] {
			PreferencesMessages.getString("CompilerConfigurationBlock.error"),  
			PreferencesMessages.getString("CompilerConfigurationBlock.warning") 
		};
			
		GridLayout layout= new GridLayout();
		layout.numColumns= 2;
		Composite othersComposite= new Composite(folder, SWT.NULL);
		othersComposite.setLayout(layout);
		
		Label description= new Label(othersComposite, SWT.WRAP);
		description.setText(PreferencesMessages.getString("CompilerConfigurationBlock.build_warnings.description")); 
		GridData gd= new GridData(GridData.FILL_HORIZONTAL | GridData.GRAB_HORIZONTAL);
		gd.horizontalSpan= 2;
		
		description.setLayoutData(gd);
		
		Composite combos= new Composite(othersComposite, SWT.NULL);
		gd= new GridData(GridData.FILL | GridData.GRAB_HORIZONTAL);
		gd.horizontalSpan= 2;
		combos.setLayoutData(gd);
		GridLayout cl= new GridLayout();
		cl.numColumns=2; cl.marginWidth= 0; cl.marginHeight= 0;
		combos.setLayout(cl);