Created Global function to unlock structures and then setup listener on the sticky menu (pop-up-menu-generator.gd) so that it can regenerate the menu with the unlocks.

global/event_bus.gd

@@ -3,6 +3,7 @@ extends Node
 signal population_update(count:int)
 signal receive_data_from_browser(args)
 signal set_structure(structure:Structure)
+signal structure_unlocked(structure:Structure)
 
 var current_scene = null
 

global/globals.gd

@@ -26,4 +26,8 @@ func set_structure(structure:Structure) -> void:
 
 	# Emit the signal to notify other nodes
 	EventBus.set_structure.emit(structure)
+
+# Used when a new structure is unlocked	
+func structure_unlocked(structure:Structure) ->void:
+	EventBus.structure_unlocked.emit(structure)
 	

mission/unit_1.02/unlock_buildings.tres

@@ -9,7 +9,7 @@ script = ExtResource("1_objective")
 type = 0
 target_count = 3
 current_count = 0
-description = "Build 3 Type A houses to unlock all building types"
+description = "Build 3 Fountains to unlock all homes!"
 completed = false
 structure = ExtResource("2_hfe31")
 

scenes/ui/sticky_builder/pop-up-menu-generator.gd

@@ -15,7 +15,10 @@ func _ready():
 	
 	# Add to group for easy refreshing of all structure menus
 	add_to_group("structure_menus")
+
+	EventBus.structure_unlocked.connect(_on_structure_unlock)
 	
+
 	# Load icons (you'll need to create or find these icons)
 	_lock_icon = load("res://sprites/sticky_builder_icons/lock.png") if ResourceLoader.exists("res://sprites/sticky_builder_icons/lock.png") else null
 	if(_lock_icon):
@@ -178,3 +181,6 @@ func _unhandled_input(event: InputEvent) -> void:
 		get_viewport().set_input_as_handled()
 		if event is InputEventMouseButton:
 			event.pressed = false
+			
+func _on_structure_unlock(structure:Structure)->void:
+	refresh()

scripts/mission/mission_loader.gd

@@ -93,6 +93,8 @@ func _unlock_starting_structures(structure_paths: Array) -> void:
 				if structure_path == possible_path:
 					structure.unlocked = true
 					found_match = true
+					# Let the rest of the game know a structure has been unlocked
+					Globals.structure_unlocked(structure)
 					break
 			
 			if found_match:

scripts/mission/mission_manager.gd

@@ -864,6 +864,7 @@ func _handle_structure_unlocking(mission):
 						if "unlocked" in structure:
 							structure.unlocked = true
 							unlocked_structures.append(structure)
+							Globals.structure_unlocked(structure)
 						found = true
 			if not found:
 				print("[Unlock]   No match found for item_path: ", item_path)