ref: 5c30140aa4d842dbb700cd6c8b9d7296fd91da84
dir: /libtk/radio.tk/
radiobutton .u -text {Upper case} -variable case -value u radiobutton .l -text {Lower case} -variable case -value l radiobutton .i -text {Ignore case} -variable case -value i pack .u .l .i -anchor w -fill x