We have some scattered expander/dropdown widgets that need hidpi icons (arrows), so they don't look blurry/upscaled on Retina displays. It's a bit of a grabbag, and some come from the same implementation, but I've grouped them here together since they should be simple to fix. * Expander button in Clear Recent History * Expander button in Places Library's bookmark details * In the Bookmark arrowpanel, the folder-picker dropdown arrow (the in-button icon, not the expander next to it) * In Customize mode, the dropdown arrow in Show/Hide Toolbars button * The secondary-actions button dropdown in doorhangers (I guess I already listed it in bug 1021958, but I'll list it here too.)