paper-dropdown-menu-light collapses after deselection

[mgiuffrida]

Fiddle: https://jsfiddle.net/mgiuffrida/ug56pybu/

After selecting a value, deselecting a value causes the dropdown menu button to collapse. Doesn't seem to matter whether it has a label or no-label-float set.

[markus1978]

I had/have the same issue. Here is what I found: paper-dropdown-menu-light uses <div id="input" tabindex="-1">&nbsp;</div> to render the selected item label. If the selection is changed to no selection, this div's content is changed to "" and not to " ". As a result the div's height is 0px and the whole component is displayed incorrectly.

If you replace paper-dropdown-menu-light's _valueChanged function with

_valueChanged: function() {
  // Only update if it's actually different.
  if (this.$.input && this.$.input.textContent !== this.value) {
    this.$.input.textContent = this.value;
    // insert   if the value is empty string to enforce correct rendering
    if (this.value == "") {
      this.$.input.innerHTML = " ";
    }
  }
  this._setHasContent(!!this.value);
},

this issue disappears.