non-menu dropdown content isn't sized correctly

[lkovaleva]

Code:

<paper-menu-button>
  <paper-button class="dropdown-trigger">Checkboxes</paper-button>
  <div class="dropdown-content">
    <paper-checkbox>Show one</paper-checkbox>
    <paper-checkbox>Show two</paper-checkbox>
    <paper-checkbox>Show three</paper-checkbox>
    <paper-checkbox>Show four</paper-checkbox>
  </div>
</paper-menu-button>

When opened dropdown has a scrollbar:

This only appears to be an issue when content is not paper-menu

Note I also had this styling applied in the above screenshot, but even without it the scrollbar still appears

<style>
  .dropdown-content > paper-checkbox {
    display: block;
    padding: 4px;
  }
</style>

[cdata]

This may be related to margins bleeding out of the div.