Adding a Drop Down Menu

How to add our own Drop Down Menu

For Most Editor Menus

With a valid menu loaded, in most sections of the Editor we can use the following code to add our own dropdown menu:

ToolMenus= unreal.ToolMenus.get()
menu = ToolMenus.find_menu("LevelEditor.MainMenu")

dropdown_menu = menu.add_sub_menu(
    owner="custom_owner", # this is used to delete menus later if needed
    section_name="",
    name="DemoTools",
    label="Demo Tools"
)
ToolMenus.refresh_all_widgets()

This will add a new Demo Tools entry to the top bar of the Editor:

The name argument is used for the programmatic name, used for the menu path:

LevelEditor.MainMenu.DemoTools

The label argument is what actually gets displayed in the UI

The owner argument is useful for if we ever want to remove our menu:

ToolMenus.unregister_owner_by_name("custom_owner")

---

For ToolBar Menus (before 5.5)

Note: In UE 5.5 Epic provided better support for the above code style to work with ToolBars, this is for UE 5.0-5.4

For ToolBar Menus such as Sequencer, the above code does not work before UE 5.5. Instead, we need to create our own Toolbar Dropdown Menu Class and use it instead.

The Dropdown Class

This is using concepts covered in the Menu Class section, but here is a minimal class that will let us add a Dropdown Menu to Sequencer:

@unreal.uclass()
class ToolbarDropdownMenu(unreal.ToolMenuEntryScript):
    """Drop down menu class that can be used with Sequencer"""

    def __init__(self, menu, name, label, section="", tooltip=""):
        super().__init__()
        self.data.advanced.entry_type = unreal.MultiBlockType.TOOL_BAR_COMBO_BUTTON
        parent_menu = menu.get_editor_property("menu_name")
        self.init_entry("custom_owner", parent_menu, section, name, label, tooltip)
        menu.add_menu_entry_object(self)

They key to this class is that its entry_type has been updated to TOOL_BAR_COMBO_BUTTON. This will allow us to add it to Sequencer and other Tool Bars

Using Our Custom Class

With our ToolbarDropdownMenu class initialized, we can run the following to add our Dropdown Menu to Sequencer:

ToolMenus = unreal.ToolMenus.get()
menu = ToolMenus.find_menu("Sequencer.MainToolBar")

dropdown_menu = ToolbarDropdownMenu(
    menu=menu,
    name="DemoTools",
    label="Demo Tools"
)
ToolMenus.refresh_all_widgets()

This will add a new Demo Tools entry to Sequencer's Toolbar: