feat: allow disabling menu on right click and add show_menu()

[felipecrs]

This PR adds two features to this crate:

1. Allows disabling showing the menu on right click (similar to how it can be done for left click)
2. Adds a method for displaying the menu manually

Which, together, fixes #254: users can disable menu on right click, update the menu on a right click event, and then display the menu once done.

PS: Claude Sonnet 4.5 has been used to generate these changes, but the code has been reviewed and changed for consistency.

Demo

Windows:

3cqD6MA7NY.mp4

Mac:

AnyDeskMSI_hKs5iFcMu9.mp4

Code for the demo

// Example demonstrating how to prevent automatic menu opening on right-click
// and manually show the menu after updating it dynamically
//
// This example shows two approaches:
// 1. Using show_menu() to immediately display the menu after updating (demonstrated here)
// 2. Using set_show_menu_on_right_click(true) to re-enable automatic opening
//
// Approach 1 is simpler and provides better UX as the menu appears instantly
// after the update without requiring another click.

use tray_icon::{
    menu::{Menu, MenuItem},
    Icon, MouseButton, MouseButtonState, TrayIconBuilder, TrayIconEvent,
};
use winit::event_loop::{ControlFlow, EventLoop};

fn main() {
    let event_loop = EventLoop::builder().build().unwrap();

    let icon = load_icon();

    // Create initial menu items
    let menu = Menu::new();
    let item1 = MenuItem::new("Item 1", true, None);
    let item2 = MenuItem::new("Item 2", true, None);
    menu.append(&item1).unwrap();
    menu.append(&item2).unwrap();

    // Build tray icon with menu_on_right_click disabled
    let tray_icon = TrayIconBuilder::new()
        .with_tooltip("Dynamic Menu Example")
        .with_icon(icon)
        .with_menu(Box::new(menu.clone()))
        .with_menu_on_right_click(false) // Disable automatic menu opening on right-click
        .build()
        .unwrap();

    println!("Tray icon created with menu_on_right_click = false");
    println!("Right-click the tray icon to see dynamic menu updates!");

    let mut counter = 2;

    #[allow(deprecated)]
    let _ = event_loop.run(move |_event, elwt| {
        elwt.set_control_flow(ControlFlow::Poll);

            // Listen for tray icon events
            if let Ok(event) = TrayIconEvent::receiver().try_recv() {
                // Check if it's a right-click down event
                if matches!(
                    event,
                    TrayIconEvent::Click {
                        button: MouseButton::Right,
                        button_state: MouseButtonState::Down,
                        ..
                    }
                ) {
                    println!("Right-click detected! Updating menu...");

                    // Update menu items dynamically
                    counter += 1;
                    
                    // Update the menu item texts
                    item1.set_text(format!("Updated Item {}", counter - 1));
                    item2.set_text(format!("Updated Item {}", counter));

                    println!("Menu updated - texts changed");

                    // Now manually show the menu after updating
                    tray_icon.show_menu();
                }

            // Note: We no longer need to handle MouseButtonState::Up
            // because we're manually showing the menu immediately after updating
            }
        });
}

fn load_icon() -> Icon {
    let (icon_rgba, icon_width, icon_height) = {
        let image = image::load_from_memory(include_bytes!("../examples/icon.png"))
            .expect("Failed to open icon path")
            .into_rgba8();
        let (width, height) = image.dimensions();
        let rgba = image.into_raw();
        (rgba, width, height)
    };
    Icon::from_rgba(icon_rgba, icon_width, icon_height).expect("Failed to open icon")
}

[felipecrs]

@amrbashir sorry for pinging you, but I think this PR is almost a no-brainer. Mind taking a look?