core-dropdown doesn't close menu when used inside custom component and multiple instances

[tonosama-atlacatl]

Here is a basic except of my custom dart/polymer component:

<a id="row-options-button" class="optionsBtn" href="#" style=""
            title="Options" on-click="{{ openDropdown }}" relative>
             <i id="ellipsisIcon" class="icon fa fa-ellipsis-v"></i>
             <core-dropdown id="optionsDropDown" class="colored" layered="true" autoCloseDisabled="false">
                 <core-selector single valueattr="label">
                    <core-item label="Display for 8 seconds"></core-item>
                 </core-selector>
             </core-dropdown>
         </a>
    </template>
</polymer-element>

The problem/bug:
Clicking on a new instance of this component does NOT close the previous opened dropdown. Sometimes this is true while clicking different elements too.

Maybe I'm missing something, but is there a global way to closing all instances of a core-dropdown, even if they reside under Shadow Dom?, as an alternative I mean...