Radio buttons turn off checkboxes

[Walton Sumner]

A group with radioBehavior checked, 3 radio buttons, and several check boxes
works as expected, except that Rev 2.6.1 (OSX and Win versions) turns off
all of the checkboxes when I click a radio button. Subgrouping the 3 radio
buttons prevents this, but that is not supposed to be necessary -
documentation says that radioBehavior should affect only buttons with style
radiobutton, so it ought to ignore those with style checkbox. Seems
hazardous for the behavior not to match documentation. Or am I doing
something wrong? 

Walt Sumner