World Clock is an extension that let you render world clocks in your browser toolbar popup. Simply add as many clocks as you want from the drop-down list in the popup. Please note that, currently 34 items are available to choose from. Before adding any item, you can set the daylight-saving value as well (i.e. -1, 0 and +1). Moreover, items in toolbar popup are draggable to your desired position. All changes are auto saved to the memory. By default, six items are added to toolbar popup, but you can remove them at any time by clicking on the cross-sign next to each item (remove button at top right corner). If you have a feature request, or found a bug to report, please fill the bug report form in the add-on's homepage (http://mybrowseraddon.com/world-clock.html).