diff --git a/addons/material_maker/engine/loader.gd b/addons/material_maker/engine/loader.gd
index b60a4bb..10f7ec4 100644
--- a/addons/material_maker/engine/loader.gd
+++ b/addons/material_maker/engine/loader.gd
@@ -3,10 +3,13 @@ extends Node
 
 const STD_GENDEF_PATH = "res://addons/material_maker/nodes"
 
-var generators = {}
+var predefined_generators = {}
 
 func _ready()-> void:
-	var gen_count = 0
+	update_predefined_generators()
+
+func update_predefined_generators()-> void:
+	predefined_generators = {}
 	for path in [ STD_GENDEF_PATH, OS.get_executable_path().get_base_dir()+"/generators" ]:
 		var dir = Directory.new()
 		if dir.open(path) == OK:
@@ -16,14 +19,9 @@ func _ready()-> void:
 				if !dir.current_is_dir() and file_name.get_extension() == "mmg":
 					var file : File = File.new()
 					if file.open(path+"/"+file_name, File.READ) == OK:
-						if !generators.has(file_name.get_basename()):
-							gen_count += 1
-						generators[file_name.get_basename()] = parse_json(file.get_as_text())
+						predefined_generators[file_name.get_basename()] = parse_json(file.get_as_text())
 						file.close()
 				file_name = dir.get_next()
-		else:
-			print("An error occurred when trying to access the path.")
-	print(gen_count)
 
 func generator_name_from_path(path : String) -> String:
 	for p in [ STD_GENDEF_PATH, OS.get_executable_path().get_base_dir()+"/generators" ]:
@@ -85,9 +83,11 @@ func create_gen(data) -> MMGenBase:
 		if types.has(data.type):
 			generator = types[data.type].new()
 		else:
-			generator = create_gen(generators[data.type])
+			generator = create_gen(predefined_generators[data.type])
 			if generator == null:
 				print("Cannot find description for "+data.type)
+			else:
+				generator.model = data.type
 		if generator != null:
 			generator.name = data.type
 	if generator == null:
diff --git a/material_maker/graph_edit.gd b/material_maker/graph_edit.gd
index 3db9108..456569a 100644
--- a/material_maker/graph_edit.gd
+++ b/material_maker/graph_edit.gd
@@ -32,8 +32,13 @@ func _ready() -> void:
 func _gui_input(event) -> void:
 	if event is InputEventKey and event.pressed:
 		var scancode_with_modifiers = event.get_scancode_with_modifiers()
-		if scancode_with_modifiers == KEY_DELETE || scancode_with_modifiers == KEY_BACKSPACE:
+		if scancode_with_modifiers == KEY_DELETE or scancode_with_modifiers == KEY_BACKSPACE:
 			remove_selection()
+	return
+	if event is InputEventMouseMotion and event.button_mask == 0:
+		for c in get_children():
+			if c is GraphNode and Rect2(c.rect_global_position, c.rect_size*c.get_global_transform().get_scale()).has_point(event.global_position):
+				hint_tooltip = c.get_slot_tooltip(c.get_global_transform().xform_inv(event.global_position))
 
 # Misc. useful functions
 func get_source(node, port) -> Dictionary:
diff --git a/material_maker/main_window.gd b/material_maker/main_window.gd
index a9c5729..59f788b 100644
--- a/material_maker/main_window.gd
+++ b/material_maker/main_window.gd
@@ -524,9 +524,12 @@ func update_preview_3d(previews : Array) -> void:
 		for p in previews:
 			gen_material.update_materials(p.get_materials())
 
+var selected_node = null
 func on_selected_node_change(node) -> void:
-	preview_2d.setup_controls(node.generator if node != null else null)
-	update_preview_2d(node)
+	if node != selected_node:
+		selected_node = node
+		preview_2d.setup_controls(node.generator if node != null else null)
+		update_preview_2d(node)
 
 func _on_Projects_tab_changed(tab) -> void:
 	var new_tab = projects.get_current_tab_control()
diff --git a/material_maker/nodes/base.gd b/material_maker/nodes/base.gd
index ee40ec6..e1a0728 100644
--- a/material_maker/nodes/base.gd
+++ b/material_maker/nodes/base.gd
@@ -5,6 +5,7 @@ var generator : MMGenBase = null setget set_generator
 
 func _ready() -> void:
 	connect("offset_changed", self, "_on_offset_changed")
+	connect("gui_input", self, "_on_gui_input")
 
 func _exit_tree() -> void:
 	get_parent().call_deferred("check_last_selected")
@@ -13,11 +14,6 @@ func _draw() -> void:
 	if generator != null and generator.has_randomness():
 		var icon = preload("res://material_maker/icons/randomness_locked.tres") if generator.is_seed_locked() else preload("res://material_maker/icons/randomness_unlocked.tres")
 		draw_texture_rect(icon, Rect2(rect_size.x-48, 4, 16, 16), false)
-		if !is_connected("gui_input", self, "_on_gui_input"):
-			connect("gui_input", self, "_on_gui_input")
-	else:
-		if is_connected("gui_input", self, "_on_gui_input"):
-			disconnect("gui_input", self, "_on_gui_input")
 
 func set_generator(g) -> void:
 	generator = g
@@ -25,8 +21,33 @@ func set_generator(g) -> void:
 func _on_offset_changed() -> void:
 	generator.set_position(offset)
 
+func _input(event) -> void:
+	_on_gui_input(event)
+
 func _on_gui_input(event) -> void:
 	if event is InputEventMouseButton and event.pressed and event.button_index == BUTTON_LEFT and Rect2(rect_size.x-48, 4, 16, 16).has_point(event.position):
 		generator.toggle_lock_seed()
 		update()
 		get_parent().send_changed_signal()
+	elif event is InputEventMouseMotion:
+		var epos = event.position
+		if Rect2(0, 0, 16, 16).has_point(epos):
+			if generator.model != null:
+				hint_tooltip = generator.model
+			return
+		elif Rect2(rect_size.x-48, 4, 16, 16).has_point(epos) and generator.has_randomness():
+			if generator.is_seed_locked():
+				hint_tooltip = "Unlock the random seed, so it can be modified by moving the node"
+			else:
+				hint_tooltip = "Lock the random seed to its current value"
+			return
+		hint_tooltip = ""
+
+func get_slot_tooltip(pos : Vector2):
+	for i in range(get_connection_input_count()):
+		if is_slot_enabled_left(i) and (get_connection_input_position(i)-pos).length() < 5:
+			return "input "+str(i)
+	for i in range(get_connection_output_count()):
+		if is_slot_enabled_right(i) and (get_connection_output_position(i)-pos).length() < 5:
+			return "output "+str(i)
+	return ""
diff --git a/material_maker/nodes/generic.gd b/material_maker/nodes/generic.gd
index a175429..2a2d7ae 100644
--- a/material_maker/nodes/generic.gd
+++ b/material_maker/nodes/generic.gd
@@ -309,7 +309,7 @@ func load_generator() -> void:
 	dialog.rect_min_size = Vector2(500, 500)
 	dialog.access = FileDialog.ACCESS_FILESYSTEM
 	dialog.mode = FileDialog.MODE_OPEN_FILE
-	dialog.add_filter("*.mmg,*.mmn;Material Maker Generator")
+	dialog.add_filter("*.mmg;Material Maker Generator")
 	dialog.connect("file_selected", self, "do_load_generator")
 	dialog.popup_centered()
 
@@ -350,6 +350,7 @@ func do_save_generator(file_name : String) -> void:
 		data.node_position = { x=0, y=0 }
 		file.store_string(JSON.print(data, "\t", true))
 		file.close()
+		mm_loader.update_predefined_generators()
 
 func update_preview_buttons(index : int) -> void:
 	for i in range(output_count):
diff --git a/material_maker/widgets/linked_widgets/link.gd b/material_maker/widgets/linked_widgets/link.gd
index b7784a0..58f8a4b 100644
--- a/material_maker/widgets/linked_widgets/link.gd
+++ b/material_maker/widgets/linked_widgets/link.gd
@@ -41,7 +41,7 @@ func find_control(gp) -> Dictionary:
 			if c.get("controls") != null:
 				for w in c.controls:
 					var widget = c.controls[w]
-					if widget != null and Rect2(widget.rect_global_position, widget.rect_size*widget.get_global_transform().get_scale()).has_point(gp):
+					if is_instance_valid(widget) and Rect2(widget.rect_global_position, widget.rect_size*widget.get_global_transform().get_scale()).has_point(gp):
 						return { node=c, widget=widget }
 	return {}