Marcus Schopen writes:

The problem that occurs is, that the tree`s open/close state is not correctly maintained over the different documents. A solution to that might be to append the state of the tree after selection of a link to the it's URL as ?tree-s=.... ; that means pass the future state of the tree to the selected page by using URL-Parameters.

Any ideas how to do that or any other ideas? I think, this is a great idea! It would avoid the cookie to save the state and would therefore be much more robust.

I have extended the TreeTag to allow explicite control of the hotspot (i.e. the icon to control opening/closing a branch). The extension is not yet general enough to support passing the future state (after the operation) but still uses the incremental state change. The extension is not easy to understand and packaged with our changes to the TreeTag. There may be another way to influence the hotspot as Zope magically adds a "target" in the left frame of its management screen. I did not yet look at how it works. You find the function to compute the new state in "TreeDisplay.TreeTag.apply_diff". Dieter