Now I know it's actually a button it's because it inherits so you go to button select the top with no px size, and no type and select the color you want, like white or yellow for example, now it's set to transparent.
That doesn't add functionality though it's just an arrow for it to do anything you use a dropdown pane.
First I thought it was a dropdown UL.

Alter Eagle, you are using a different wireframe.css than what I have (and probably Wayan).

You do not have in your wireframe.css:

.button.dropdown::after {
border-color: transparent;
border-top-color: inherit
}

This is creating the problem for us. If I delete that in my wireframe.css after I export the button arrow appears.

They will probably release a fix for this as Wayan indicated.

OK...catching up. That is a fix for us to make the arrow appear. Thanks !

I built that button pane dropdown in an earlier build, but I have updated those pages since with 2309.
At any rate I checked it with firebug and saw the arrow border was set to inherit so I just set the border color inside RSD with the BORDER style in the 2309 build. No need for a px size or even a border type so grey out the button class and apply the color to dropdown. Goes to the class set and fixes it.

Got crossed there, it's in the step by step tutorial I did too

Yes that works better....

The down arrow for the class dropdown being invisible should have been remedied in the latest build

Please let us know how it goes! We hope to post full change logs later today.