Minimize windows into application icon

This problem is new with Acrobat DC and a wxWidgets plugin. I switch on the checkbox to 'Minimize windows into application icon' in the Dock Preferences... settings. I iconize the window. With iconize(true) the window shortly appears before it is hidden. Asking the window, if it IsShownOnScreen() returns true but the window is not visible. If I switch off the checkbox in the Dock Prefs iconize works fine.

A workaround is show(false) and show(true). But then the window will be rendered always two times. Is there a call to get the state of the checkbox in the Dock Prefs?