Bug 42655 SourceAttachmentBlock does not use dialog font for all widgets [dialogs] [build path]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
public void changeControlPressed(DialogField field) {
			attachmentChangeControlPressed(field);			
		}
		
		
		public void dialogFieldChanged(DialogField field) {
			attachmentDialogFieldChanged(field);
		}
	}
	
	private void attachmentChangeControlPressed(DialogField field) {
		if (field == fFileNameField) {
			IPath jarFilePath= isVariableEntry() ? chooseExtension() : chooseExtJarFile();
			if (jarFilePath != null) {
				fFileNameField.setText(jarFilePath.toString());
			}
		}	
	}