Problems with buttons with primary icon

Problems with buttons with primary icon

I'm not sure what's going on here.  I have a stock jqueryui install, latest version.  When I use the jqueryui button functionality with a left (primary) icon, the button appears at the upper left, and the text appears below.

I tried copying the demo source and running it on my own web page, and it happens there too (see screencap).  What am I missing?