A document is opened in floating view.
When the "Esc" button is pressed, the window closes immediately.
When working with documents, this is a problem. Often the window is closed by accident because another action should be interrupted (e.g. tracing).
Either a pop-up window should appear (like closing the client, so that the user has to confirm the closure) or the shortcut for the closure-action of floating views should be changed (disable or another key combination).
