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
gd= new GridData(GridData.FILL);
		gd.horizontalSpan= 2;
		gd.widthHint= fPixelConverter.convertWidthInCharsToPixels(60);
		description.setLayoutData(gd);
		
		label= PreferencesMessages.getString("CompilerConfigurationBlock.resource_filter.label"); 
		text= addTextField(othersComposite, label, PREF_RESOURCE_FILTER, 0, 0);
		gd= (GridData) text.getLayoutData();
		gd.grabExcessHorizontalSpace= true;
		gd.widthHint= fPixelConverter.convertWidthInCharsToPixels(10);
		
		return othersComposite;
	}
	private Composite createProblemsTabContent(Composite folder) {
		String[] errorWarningIgnore= new String[] { ERROR, WARNING, IGNORE };
		
		String[] errorWarningIgnoreLabels= new String[] {
			PreferencesMessages.getString("CompilerConfigurationBlock.error"),  
			PreferencesMessages.getString("CompilerConfigurationBlock.warning"), 
			PreferencesMessages.getString("CompilerConfigurationBlock.ignore") 
		};
		
		String[] enabledDisabled= new String[] { ENABLED, DISABLED };
			
		GridLayout layout= new GridLayout();
		layout.numColumns= 2;
		
		Composite problemsComposite= new Composite(folder, SWT.NULL);
		problemsComposite.setLayout(layout);
		Label description= new Label(problemsComposite, SWT.WRAP);