Main canvas: Add undo-redo functionality

Use the inner properties of the block script (block_trees and
generated_script) for the do / undo.

Connect to the EditorUndoRedoManager version_changed signal to reload
the canvas.

Author: manuq

addons/block_code/ui/main_panel.gd

@@ -28,6 +28,17 @@ func _ready():
 
 	# Setup block scripting environment
 	block_code_tab = eia.Utils.find_child_by_name(eia.context_switcher, "Block Code")
+	undo_redo.version_changed.connect(_on_undo_redo_version_changed)
+
+
+func _on_undo_redo_version_changed():
+	if _current_block_code_node == null:
+		return
+
+	var block_script: BlockScriptData = _current_block_code_node.block_script
+	_picker.bsd_selected(block_script)
+	_title_bar.bsd_selected(block_script)
+	_block_canvas.bsd_selected(block_script)
 
 
 func _on_button_pressed():
@@ -56,14 +67,16 @@ func save_script():
 	var block_script: BlockScriptData = _current_block_code_node.block_script
 
 	undo_redo.create_action("Modify %s's block code script" % _current_block_code_node.get_parent().name)
-	undo_redo.add_undo_property(_current_block_code_node, "block_script", block_script)
+	undo_redo.add_undo_property(_current_block_code_node.block_script, "block_trees", _current_block_code_node.block_script.block_trees)
+	undo_redo.add_undo_property(_current_block_code_node.block_script, "generated_script", _current_block_code_node.block_script.generated_script)
 
 	var block_trees := _block_canvas.get_canvas_block_trees()
 	var generated_script = _block_canvas.generate_script_from_current_window(block_script.script_inherits)
 	block_script.block_trees = block_trees
 	block_script.generated_script = generated_script
 
-	undo_redo.add_do_property(_current_block_code_node, "block_script", block_script)
+	undo_redo.add_do_property(_current_block_code_node.block_script, "block_trees", block_trees)
+	undo_redo.add_do_property(_current_block_code_node.block_script, "generated_script", generated_script)
 	undo_redo.commit_action()