change language in "grammar and spelling" on OS X

in case you want to change the language in the "grammar and spelling" dialog box the short cut 

CMD+SHIFT+: comes very handy...

well, but then you are stuck with a floating windows - grab the mouse and change the setting. now,

CTRL+F6 comes handy - this should focus the floating window.

after the first switch the 

SHIFT+TAB comes handy to switch to the language field. when leaving the dialog box open, now, the language is pre selected...