Widget Tree DOM
------ ---- ---
w1 ------ nw1
| |
w2 ------ nw2
| |
we1 ----- nwe1 ------- e1
| \ | \ | \
| we2 -- | - nwe2 --- | - e2
w3 ------ nw3 |
| | |
we3 ----- nwe3 ------- e3