Doorhanger for plugins nearly empty, buttons w/o labels/text

[Archaeopteryx]

Firefox 24.0 on Windows XP SP3
NoScript 2.6.8.4

Steps to reproduce:
1. Install NoScript and restart Firefox.
2. Visit http://manfred-ammer.de/
3. In the upper left corner, the site embeds a midi file as background music. Click on the blocking placeholder and confirm the warning. I don't have the required QuickTime plug-in installed.
Actual result: Two doorhanger icons are shown in the left of the location bar. The second one is for downloading QuickTime, the first one is nearly empty and has only text on one of three buttons ("Show all"). This seems to be the multiple plug-in doorhanger, see bhearsum's click to play page.