underline mixins may need tweaking (have to override 2 in order to hide underline)

[valdrinkoshi]

From @ktiedt on April 27, 2016 18:21

Description

In the demo it explains how to remove the underline from a paper-dropdown-menu however it doesnt work because --paper-inout-container-underline-focus is also not overridden, as seen here: https://github.com/PolymerElements/paper-dropdown-menu/blob/master/demo/index.html#L218-L221

Expected outcome

Would not expect to have to override both --paper-input-container-underline and --paper-input-container-underline-focus to hide the underline

Actual outcome

underline appears when you click the paper-dropdown-menu that is said to have no underline.

Live Demo

https://elements.polymer-project.org/elements/paper-dropdown-menu?active=paper-dropdown-menu&view=demo:demo/index.html

Copied from original issue: PolymerElements/paper-dropdown-menu#155

[valdrinkoshi]

Will move this issue to paper-input, as those are mixins of paper-input

[notwaldorf]

It would be nice to add a demo of how to style the underline

[ktiedt]

Ideally that does not involve overriding two separate css vars ;)

[yaqihu]

Would it be possible to keep the underline appear when the dropdown is opened?
Right now, for paper-dropdown-menu, it disappears when the dropdown is opened, which causes a flash visually.