An event for treeview checkbox check ?

Hello, I am struggling in merging GUITreeViewEx, Shelltristate and enhancing to handle a third state that means : some items under are selected. I have difficulties handling expand order and key Space (especially when node is collapsed). Here the zip with UDF and and example. The problem I might need some advice to handle : 1- When load Treeview, have a correct settings of the checkbox for a tristate tree 2 - Handle keyboard used for walking in tree Chic

You have to catch TVN_ITEMCHANGED notification in WM_NOTIFY event and test NewState/OldState change See here for API reference https://msdn.microsoft.com/en-us/library/windows/desktop/bb773526(v=vs.85).aspx https://msdn.microsoft.com/en-us/library/windows/desktop/bb773425(v=vs.85).aspx It's similar to ListView with checkboxes where is LVN_ITEMCHANGED notification event where AutoIt's code looks like this: GUIRegisterMsg($WM_NOTIFY, "WM_Notify_Events")