first pass - 

1)
o[t]:aXbYc
O[T]:XY
-
[T]abc if no sticky ops in O

2)
o[t]:aXbYc
O[T]:YX
-
[T]abc if no sticky ops in O

3)
o[t]:aXbYc
O[T]:XY
-
[T]abc if sticky ops in O and no selection ops in a or b

4) (tricky case)
o[t]:aXbYc
O[T]:YX
-
[T]abc if sticky ops in Y and no selection ops in a or b or X