Dear @Kent_Starup,
please forgive me but I still don't understand the issue: By running TIM's app and yours, it seems to me that they have the same bahaviour...
Anyway, If @TIMAI2's app has solved, don't waste any more time reading this post and ignore it. 
EDIT:> if the issue is that the list_picker uses the whole screen (the whole display) masking off anything is behind it, you shall use the Spinner instead. The Spinner allows you to show a popup whose hor and vert sizes are settable. Therefore you can have the menu (the spinner behaves 90% as a listpicker) that can appear and disapper in the same Screen. It's just a matter to display or hide it, or to resize it in runtime (i.e. to set its size to H1,V1 pixels when you want to make it to disappear 
)
EDIT II > moreover if you want to show and hide a menu in an overlapped layer of the display (like if it was visually superimposed) you can use the @VSATISH13 nice extension called overlapview that you can find here:
Best wishes.