Thanks for the answer.
Your Code doesnt work 100% for me, but it helped me alot.
1.) It only works for checkboxes that get populated as unchecked because of
var
tri = $(
".DisabledCheckBox"
, sender.get_element()).siblings(
".rtUnchecked"
);
2.) I had to swap the checked and unchecked states from your image, because it got loaded wrongly. (Image is attached)
To fix the first point i have modified your code to the following: (improvements are welcome)
And added the same function to OnClientNodePopulated in my treeView.
Also i'd like to mention, that this feature was wished for in May 17, 2005. So, i hope it will be added some day.
More than 6 Years is a really long time.