Never done this yet, but can you fork the widget and add event-handling to it? Event-handling will allow you to set the 'on enter settings' to respond like you described.
@Aleksandar you want to have a blocking progress bar to do this. What type of functionality is triggered that in turn triggers the progress bar?
To show an underlay (block content):
window.mx.ui.showUnderlay(200);
To hide it again (release block of content):
window.mx.ui.hideUnderlay(200);
Hope this helps.
If you need help changing the widget to add the code to the correct locations just let me know.
Best regards,
Mitchel Mol
Aelion
Contact me via my Mx profile or LinkedIn