if you open the Tag Editor in a floating window (right click/ Edit)
the problem is that the buttons in the top of this window share the same foreground properties as the right click context menu. This works fine in most cases, but in this case not. So for the next update i've added a new element to override the text which you would need to set:
<element id="Toolbar.MenuTextOverride" fg="0,0,0" />