Enabling transaction in Spring MVC - spring-mvc

Question

My application is working well, but I´m not sure why I needed to configure the way I did.
The issue is that transactions must be enabled in both contexts, root and dispatcher.
Why is this necessary?
The app is configured like this:
public class MvcInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
#Override
protected Class<?>[] getRootConfigClasses () {
return new Class<?>[] {RootConfig.class};
}
#Override
protected Class<?>[] getServletConfigClasses () {
return new Class<?>[] {WebMvcConfig.class};
}
}
Then
#Configuration
#Import(value = {
DataSourceConfig.class,
JpaConfig.class,
SecurityConfig.class
})
#ComponentScan(
basePackages = {"com.**.service", "com.**.mail", "com.core.config"},
excludeFilters = {
#Filter(Configuration.class),
#Filter(Controller.class),
#Filter(RestController.class)
})
#EnableAsync
#EnableScheduling
#EnableAspectJAutoProxy
#EnableTransactionManagement
public class RootConfig {
// Beans Config...
}
Finally
#Configuration
#ComponentScan(basePackages = {"com.web"})
#EnableWebMvc
#EnableTransactionManagement
public class WebMvcConfig extends WebMvcConfigurerAdapter {
// Beans Config ...
}
Note:
Transactions are just managed in the Service Layer.
That #EnableTransactionManagement is present in both config
classes.
If I remove the one in WebMvcConfig, transactions will not be injected in the service layer when accesed from a Controller class. Even though the service layer is scanned by the root context.
If I remove the one in RootConfig, transactions will not be injected in the service layer when accesed for example by Spring Security.
Is there any way to enable transactions globally?