The bug
Opening the structure block GUI does not pause the game like the command block GUI does.
Expected behavior
As mentioned in the comments of MC-112415 it might be better if the game would only be paused in the ESC
menu and its sub menus to make it more consistent with multiplayer.
How to reproduce
Place a structure block:
/setblock ~ ~ ~ structure_block
Use a lava bucket to place a lava source next to the structure block
Quickly open the structure block GUI
→ ❌ The lava continues to flow while the GUI is open
Confirmed in 1.16.1 and 20w28a. Easy way to reproduce:
Place a structure block:
Use a lava bucket to place a lava source next to the structure block
Quickly open the structure block GUI
→ ❌ The lava continues to flow while the GUI is open