[Menu] Does not display in Popover

[mbrookes]

Per gitter discussion, because the Menu component has position:absolute, it falls outside normal HTML flow when rendered inside a Popover, and so does not appear.

The Popover collapses to 0 width and height if there are no other children, or collapses to the size of the other children and shows only the portion of Menu that this exposes.

As a workaround you can applying style={{position: 'static'}} to Menu, but it would be preferable if it was un-positioned (or relatively positioned) by default. Any component that uses menu and requires it to be absolutely positioned can set that itself.

[oliviertassinari]

because the Menu component has position:absolute

Looks like you are right 😳. https://github.com/callemall/material-ui/blob/master/src/menus/menu.jsx#L154
Can't we just remove this position property? I don't really see the use case.

[mbrookes]

I hope so, but I didn't just want to submit a PR without opening an issue first, in case it was that way for a reason, or other would break other components if they depend on this property, and don't set it explicitly.

[alitaheri]

@oliviertassinari It was there for the previous way of using it. when popover wan't around anymore. I think we can remove it. @mbrookes Will you do the honors? 👍 👍 Thanks for creating this issue here.

[mbrookes]

Fixed in #2455.