You can use the following built-in functions with dialog  regions and dialog controls.

 

ancestry of

background of and foreground of

border of

bottom [of]

exists

handle of

left [of]

object

parameter [of]

priority of

right [of]

top [of]

text of

visibility of

window xsize [of] and window ysize [of]

window xposition [of] and window yposition [of]

xcursor [of] and ycursor [of]

xmiddle [of] and ymiddle [of]

xposition and yposition

xsize [of] and ysize [of]