Is there an existing issue for this?

• I have searched the existing issues
• I have read the guide to filing a bug

Use case

Currently showMenu (and classes that use it, such as PopupMenuButton) has a hard-coded 300ms animation when the menu opens or closes. This cannot be modified by any means I have discovered.

This is inconsistent with MenuAnchor-based menus, which have no animation at all, and particularly for right-click context menus it feels far too slow.

Proposal

Looking at the code, it would be fairly straightforward to allow the duration to be overridden via an optional parameter to showMenu and then passed through to the _PopupMenuRoute that's created to service the call. Ideally, PopupMenuButton and friends would also accept that optional parameter and pass it through to showMenu.