diff --git a/graph_node_renderer/bottom_dock.gd b/graph_node_renderer/bottom_dock.gd
index 3632bd5..e40df61 100644
--- a/graph_node_renderer/bottom_dock.gd
+++ b/graph_node_renderer/bottom_dock.gd
@@ -13,5 +13,5 @@ func _ready() -> void:
 		set_tab_title(i, tab_names[i])
 
 
-func rebuild_variable_tree(data: Dictionary) -> void:
+func rebuild_variable_tree(data: Dictionary = {}) -> void:
 	variable_viewer.rebuild_variable_tree(data)
diff --git a/graph_node_renderer/deck_holder_renderer.gd b/graph_node_renderer/deck_holder_renderer.gd
index 777fb8d..c1b110d 100644
--- a/graph_node_renderer/deck_holder_renderer.gd
+++ b/graph_node_renderer/deck_holder_renderer.gd
@@ -315,6 +315,8 @@ func close_tab(tab: int) -> void:
 	tab_container.close_tab(tab)
 	if tab_container.get_tab_count() == 0:
 		bottom_dock.variable_viewer.disable_new_button()
+		bottom_dock.rebuild_variable_tree()
+		sidebar.clear_node_list()
 		sidebar.set_edited_deck()
 
 
diff --git a/graph_node_renderer/sidebar/sidebar.gd b/graph_node_renderer/sidebar/sidebar.gd
index 6ad7368..95c4c76 100644
--- a/graph_node_renderer/sidebar/sidebar.gd
+++ b/graph_node_renderer/sidebar/sidebar.gd
@@ -88,6 +88,11 @@ func refresh_node_list(_unused = null) -> void:
 		node_list_menu.add_child(hb)
 
 
+func clear_node_list() -> void:
+	for i in node_list_menu.get_children():
+		i.queue_free()
+
+
 #func _set_button_text(new_text: String, button: Button) -> void:
 	# this was also bad. "Cannot convert argument 2 from Object to Object" 🙃
 	#button.text = "\"%s\"" % new_text
diff --git a/graph_node_renderer/variable_viewer.gd b/graph_node_renderer/variable_viewer.gd
index e8998c4..5c0c403 100644
--- a/graph_node_renderer/variable_viewer.gd
+++ b/graph_node_renderer/variable_viewer.gd
@@ -145,6 +145,8 @@ func add_item(item_name: String, item_value: Variant, parent: TreeItem = root, c
 	
 	set_item_value(item, item_value)
 
+	# TODO: TreeItem has a barely-documented quirk that can make the RANGE cell mode
+	# into a dropdown if the item text is comma-separated values, so use that
 	item.set_text(2, DeckType.type_str(type))
 	item.set_metadata(2, type)
 	if item_value is Dictionary: