html template with [hidden] fails in IE9/10

[JcDestiny]

On the ie10, the emoji selection box pops up automatically. eg：<div class="emoji-search" [ngClass]="popupAnchor" [hidden]="!popupOpen "> you should replace it with <div class="emoji-search" [ngClass]="popupAnchor" [style.display]="popupOpen ? 'block' : 'none'">, so you can show it correctly！