Z-order issue on planet screen

Version: 0.77 Beta
Details: In some cases, popups are not visible because they end up behind other content 
How to reproduce: 

1. Open planet screen
2. Click Tech on top left corner
   • note that the Tech window does not appear
3. Click on a citizen on the top right as you would to change their occupation or imprison them
   • note that the Citizen Orders popup does not appear
4. Close the planet screen
   • note that the Tech window is visible
   • note that the Citizen Orders popup is visible

Files: N/A