Change get_tree().get_root() to get_window() in TransparentChecker.gd

.gitignore

@@ -2,6 +2,7 @@
 # Godot-specific ignores
 .import/
 .godot/
+override.cfg
 
 # Imported translations (automatically generated from CSV files)
 *.translation

src/Autoload/Global.gd

@@ -174,7 +174,7 @@ var single_window_mode := true:
 		if OS.has_feature("editor"):
 			return
 		ProjectSettings.set_setting("display/window/subwindows/embed_subwindows", value)
-		ProjectSettings.save_custom(OVERRIDE_FILE)
+		ProjectSettings.save_custom(root_directory.path_join(OVERRIDE_FILE))
 ## Found in Preferences. The modulation color (or simply color) of icons.
 var modulate_icon_color := Color.GRAY
 ## Found in Preferences. Determines if [member modulate_icon_color] uses custom or theme color.
@@ -379,7 +379,7 @@ var tablet_driver := 0:
 			return
 		var tablet_driver_name := DisplayServer.tablet_get_current_driver()
 		ProjectSettings.set_setting("display/window/tablet_driver", tablet_driver_name)
-		ProjectSettings.save_custom(OVERRIDE_FILE)
+		ProjectSettings.save_custom(root_directory.path_join(OVERRIDE_FILE))
 
 # Tools & options
 ## Found in Preferences. If [code]true[/code], the cursor's left tool icon is visible.
@@ -816,7 +816,7 @@ func _renderer_changed(value: int) -> void:
 #	ProjectSettings.set_initial_value("rendering/quality/driver/driver_name", "GLES2")
 #	var renderer_name := OS.get_video_driver_name(renderer)
 #	ProjectSettings.set_setting("rendering/quality/driver/driver_name", renderer_name)
-#	ProjectSettings.save_custom(OVERRIDE_FILE)
+#	ProjectSettings.save_custom(root_directory.path_join(OVERRIDE_FILE))
 
 
 ## Use this to prepare Pixelorama before opening a dialog.

src/UI/Nodes/TransparentChecker.gd

@@ -45,10 +45,10 @@ func update_transparency(value: float) -> void:
 	# Change the transparency status of the parent viewport and the root viewport
 	if value == 1.0:
 		get_parent().transparent_bg = false
-		get_tree().get_root().transparent_bg = false
+		get_window().transparent_bg = false
 	else:
 		get_parent().transparent_bg = true
-		get_tree().get_root().transparent_bg = true
+		get_window().transparent_bg = true
 
 	# Set a minimum amount for the fade so the canvas won't disappear
 	material.set_shader_parameter("alpha", clampf(value, 0.1, 1))