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
description.setText(PreferencesMessages.getString("CompilerConfigurationBlock.problems.description")); 
		GridData gd= new GridData();
		gd.horizontalSpan= 2;
		gd.widthHint= fPixelConverter.convertWidthInCharsToPixels(50);
		description.setLayoutData(gd);
		Composite combos= new Composite(problemsComposite, SWT.NULL);
		gd= new GridData();
		gd.horizontalSpan= 2;
		combos.setLayoutData(gd);
		GridLayout cl= new GridLayout();
		cl.numColumns=2; cl.marginWidth= 0; cl.marginHeight= 0;
		combos.setLayout(cl);
		String label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_unreachable_code.label"); 
		addComboBox(combos, label, PREF_PB_UNREACHABLE_CODE, errorWarningIgnore, errorWarningIgnoreLabels, 0);	
		
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_invalid_import.label"); 
		addComboBox(combos, label, PREF_PB_INVALID_IMPORT, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_unused_local.label"); 
		addComboBox(combos, label, PREF_PB_UNUSED_LOCAL, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_unused_parameter.label"); 
		addComboBox(combos, label, PREF_PB_UNUSED_PARAMETER, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_unused_imports.label"); 
		addComboBox(combos, label, PREF_PB_UNUSED_IMPORT, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_unused_private.label"); 
		addComboBox(combos, label, PREF_PB_UNUSED_PRIVATE, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_non_externalized_strings.label"); 
		addComboBox(combos, label, PREF_PB_NON_EXTERNALIZED_STRINGS, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_deprecation.label"); 
		addComboBox(combos, label, PREF_PB_DEPRECATION, errorWarningIgnore, errorWarningIgnoreLabels, 0);
		label= PreferencesMessages.getString("CompilerConfigurationBlock.pb_deprecation_in_deprecation.label");