GUI jumps back into its default position, set position

I've created twi GUIs. When using a pushbutton in the first one, the second one is supposed to open in the same position as the first one. My code in the first GUI is p = get(gcf,'OuterPosition'); % get position of this GUI setappdata(0,'p',p); % write position into root directory second_GUI; % open another GUI

My code in the second GUI is p = getappdata(0,'p'); % get position from root directory set(gcf,'position',p); % set position of this GUI

It works BUT as soon as I move the first GUI a slight bit off-screen the second GUI will open in that off-screen position but then jump back into its default-position immediatly.

Any ideas?