There are several OS-specific widgets that are extremely useful when creating desktop applications, which could be provided in some platform-agnostic way. This issue isn't demanding that they be implemented by winit directly, but there should be some official way to create them, either in winit itself or some associated downstream crate. How should we handle this?

Widgets that could be provided:

• File save/open dialogs
• Confirmation dialogs (e.g. Do you want to save before closing dialogs)
• Menu bars
• Right-click menus
• Taskbar/Dock menus (the right-click menu when you click on a window's taskbar icon)

#403 #427