[Yegor]

There is two threads explaining how to show a modal Dialog from background process, also the problem of white screen with the displayed dialog was mentioned, but there was no answer how to get the Dialog dislpayed with all previous screen content still visible...

Any idea?

[Dougsg38p]

What is meant by "all previous screen content" ?

If you push a modal dialog from background (either passing the job off to the event thread using invokeLater() or by synchronizing with the event lock), it will appear over top of the existing screen content (if this is what you are asking).

[Yegor]

Right, the dialog is shown in the middle of the screen, but all the screen around it is white.

[Dougsg38p]

Push the dialog modal, with the "global" attribute. This will appear over whatever screen is currently displayed.