spawn window on top of widget, like popover menu

[suptimal]

after "some" trial and error, i came up with this "code" to show a window centered above a eventbox in my bar.
my question: did i overlook something, is there another method? This one works but i have minor jumping while widgets load.

from gi.repository import GLib

class MyPopupWindow(widgets.EventBox):
    def __init__(self, namespace, box_label="click_me", label="HELLO"):
        self.overlay_widget = widgets.Box(
            child=[widgets.Label(label=label, style="background-color: teal;")],
            style="background-color: cyan;",
            halign="start",
        )
        self.popup_window = widgets.Window(
            namespace=namespace,
            exclusivity="ignore",
            anchor=["top", "left", "right", "bottom"],
            child=widgets.Overlay(
                child=widgets.Button(
                    vexpand=True,
                    hexpand=True,
                    can_focus=False,
                    on_click=self.__on_click,
                ),
                overlays=[self.overlay_widget],
            ),
            visible=False
        )
        super().__init__(
            child=[widgets.Label(label=box_label)],
            on_click=self.__on_click,
        )
        self.overlay_widget.connect("realize", self.__update_overlay_position)

    def __update_overlay_position(self, _) -> None:
        root = self.get_root()
        if not root:
            return

        popup_width = self.overlay_widget.get_width()
        _, rect = self.compute_bounds(root)
        margin_left = rect.get_bottom_left().x - popup_width/2 + self.get_width()/2
        margin_hor = root.get_height()

        # Clamp margin_left so popup does not go outside root
        if margin_left + popup_width > root.get_width():
            margin_left = root.get_width() - popup_width

        # "support" top and bottom bar
        if "top" in self.get_root().anchor:
            self.overlay_widget.style = f"margin-left: {margin_left}px; margin-top:{margin_hor}px;"
            self.overlay_widget.valign="start"
        else:
            self.overlay_widget.style = f"margin-left: {margin_left}px; margin-bottom:{margin_hor}px;"
            self.overlay_widget.valign="end"

        # If width is 0 but widget is visible, retry later
        if popup_width == 0 and self.popup_window.visible:
            GLib.idle_add(self.__update_overlay_position, _)
            print("retry")
            return
        
    def __on_click(self, _) -> None:
        self.popup_window.visible = not self.popup_window.visible

[suptimal]

my current version of this.

from gi.repository import GLib
class MyPopupWindow(widgets.EventBox):
    def __init__(self, namespace, event_content=None, overlay_content=None):
        """
        :param namespace: widget namespace for the popup window
        :param event_content: list of widgets to show in the EventBox (default: a Label)
        :param overlay_content: list of widgets to show in the overlay (default: a Label)
        """
        # Overlay content
        if overlay_content is None:
            overlay_content = [
                widgets.Label(label="HELLO", style="background-color: teal;")
            ]

        self.overlay_widget = widgets.Box(
            child=overlay_content,
            style="background-color: cyan;",
            halign="start",
        )

        # Popup window with overlay
        self.popup_window = widgets.Window(
            namespace=namespace,
            exclusivity="ignore",
            anchor=["top", "left", "right", "bottom"],
            child=widgets.Overlay(
                child=widgets.Button(
                    vexpand=True,
                    hexpand=True,
                    can_focus=False,
                    on_click=self.__on_click,
                ),
                overlays=[self.overlay_widget],
            ),
            visible=False
        )

        # Event box content
        if event_content is None:
            event_content = [widgets.Label(label="click_me")]

        super().__init__(
            child=event_content,
            on_click=self.__on_click,
        )

        self.overlay_widget.connect("realize", self.__update_overlay_position)

    def __update_overlay_position(self, _) -> None:
        root = self.get_root()
        if not root:
            return

        popup_width = self.overlay_widget.get_width()
        # Retry if width is 0
        if popup_width == 0 and self.popup_window.visible:
            GLib.idle_add(self.__update_overlay_position, _)
            return

        _, rect = self.compute_bounds(root)
        margin_left = rect.get_bottom_left().x - popup_width / 2 + self.get_width() / 2
        margin_hor = root.get_height()

        # Clamp margin_left so popup does not go outside root
        if margin_left + popup_width > root.get_width():
            margin_left = root.get_width() - popup_width

        # "support" top and bottom bar
        if "top" in self.get_root().anchor:
            self.overlay_widget.style = f"margin-left: {margin_left}px; margin-top:{margin_hor}px;"
            self.overlay_widget.valign = "start"
        else:
            self.overlay_widget.style = f"margin-left: {margin_left}px; margin-bottom:{margin_hor}px;"
            self.overlay_widget.valign = "end"

    def __on_click(self, _) -> None:
        self.popup_window.visible = not self.popup_window.visible

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