Remove block.on_canvas

Instead, check if a block is on the canvas using `Node.is_ancestor_of`.
This avoids needing to keep the property in sync between multiple
places.

addons/block_code/drag_manager/drag_manager.gd

@@ -42,7 +42,6 @@ class Drag:
 		assert(block.get_parent() == null)
 
 		add_child(block)
-		block.on_canvas = false
 		block.position = -offset
 
 		_block = block
@@ -92,7 +91,7 @@ class Drag:
 			push_error("Warning: snap point %s does not reference its parent block." % _snap_point)
 			return false
 
-		if not _snap_point.block.on_canvas:
+		if not _block_canvas.is_ancestor_of(_snap_point):
 			# We only snap to blocks on the canvas:
 			return false
 

addons/block_code/ui/block_canvas/block_canvas.gd

@@ -32,7 +32,6 @@ func _populate_block_scenes_by_class():
 func add_block(block: Block, position: Vector2 = Vector2.ZERO) -> void:
 	block.position = position
 	block.position.y += _window_scroll.scroll_vertical
-	block.on_canvas = true
 	_window.add_child(block)
 	_window.custom_minimum_size.y = max(block.position.y + EXTEND_MARGIN, _window.custom_minimum_size.y)
 
@@ -83,7 +82,6 @@ func load_tree(parent: Node, node: SerializedBlockTreeNode):
 	for prop_pair in node.serialized_block.serialized_props:
 		scene.set(prop_pair[0], prop_pair[1])
 
-	scene.on_canvas = true
 	parent.add_child(scene)
 
 	var scene_block: Block = scene as Block

addons/block_code/ui/blocks/block/block.gd

@@ -23,8 +23,6 @@ signal modified
 ## The next block in the line of execution (can be null if end)
 @export var bottom_snap_path: NodePath
 
-var on_canvas: bool = false
-
 var bottom_snap: SnapPoint
 
 

addons/block_code/ui/blocks/utilities/snap_point/snap_point.gd

@@ -35,7 +35,6 @@ func set_snapped_block(snapped_block: Block) -> Block:
 
 	if snapped_block:
 		add_child(snapped_block)
-		snapped_block.on_canvas = block.on_canvas
 
 	if snapped_block and orphaned_block:
 		var last_snap = _get_last_snap(snapped_block)