c# - WPF Secondary window snapshots main window -

an wpf project has mainwindow holding multiple books (in case one).

the pencil icon in fact button creating new instance of bookedit window , showing it. clicking should show following (and used so).

my issue recently, secondary window starts snapshotting mainwindow , showing portion of part of window:

and keeps doing when move window:

why happen? issue gpu/whatever? cannot test software on device.

i removed zindex solution.

edit 1:

it should noted books mainwindow generated behind using children.add

button newbutt = new button();                 newbutt.background = null;                 newbutt.setresourcereference(control.styleproperty, "booktoolbarbutton");                 newbutt.click += new routedeventhandler(filehandler.editbook);                 image pencil = new image();                 pencil.source = new bitmapimage(new uri("pack://application:,,,/images/pencil.png"));                 newbutt.content = pencil;                 sp.children.add(newbutt); 

editbook():

string name = (((sender button).parent stackpanel).parent grid).name;         if (system.string.isnullorempty(name)) console.writeline("error: book not hold ");         else         {             console.writeline("editting book {0}", name);             bookedit bedit = new bookedit("books/" + name + ".json");             bedit.show();         }