Steps to Reproduce

run the attachment select-all-ignored-click-1.zul

case 1)
select one by one: aaa, bbb, ccc -> select all checkmark appears
unselect all

case 2) (same as 1 just with tree)
select one by one: 111, 222, 333 -> "select all" checkmark gets checked automatically
unselect all

case 3) (only in tree)
click "select all" checkbox in tree
unselect one by one: 111, 222, 333 -> "select all" checkmark get unchecked automatically
select all

Current Result

in all 3 cases the "select all" checkbox has to be clicked twice to take effect
(seems like the first click is ignored)

Expected Result

un/select all should take effect after the first click

(if impossible to address all 3 cases (due to load on demand uncertainty) make tree/listbox behave consistently)

Debug Information

Workaround