21.2-b7 and -b8 have toolbars which "lag" somehow in Gnus

When running Gnus and entering a *Summary* buffer, the toolbar shown includes all the *Group* icons; tool tips in the minibuf when passing the mouse over these show that they will in fact execute *Group* functions. As soon as any article is displayed, the correct toolbar icons show up. Also, if one merely switches out to another buffer and back to *Summary*, the correct icons show up. Screenshots of the difference between 20.4's correct and 21.2's incorrect display are at http://www.cs.cmu.edu/~karl/pgnus/wrong-toolbar/, as seen immediately upon entering a group. I notice that, when leaving one *Summary* and entering another, the text cursor does seem to spend a lot of time in the *Group* buffer that I don't witness under 20.4. (I'm running an X11 connection over a 33K phone line, so the time spent this way is quite noticeable.)