Background: Disable/enable conditional properties

The "is_pointy_value" property depends on the block type to be Value.
And the "control_part" property depends on the block type to be Control.

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

@@ -37,6 +37,7 @@ func _set_color(new_color):
 func _set_block_type(new_block_type):
 	block_type = new_block_type
 	queue_redraw()
+	notify_property_list_changed()
 
 
 func _set_control_part(new_control_part):
@@ -49,6 +50,13 @@ func _set_is_pointy_value(new_is_pointy_value):
 	queue_redraw()
 
 
+func _validate_property(property: Dictionary):
+	if property.name == "control_part" and block_type != Types.BlockType.CONTROL:
+		property.usage |= PROPERTY_USAGE_READ_ONLY
+	elif property.name == "is_pointy_value" and block_type != Types.BlockType.VALUE:
+		property.usage |= PROPERTY_USAGE_READ_ONLY
+
+
 func _ready():
 	parent_block = BlockTreeUtil.get_parent_block(self)
 	parent_block.focus_entered.connect(queue_redraw)