EDIT

The wizard for selection of areas for the distribution editor should be improved.

• while opening the wizard the vocabularies are not correctly marked if the whole vocabulary or only parts of it should be used in the distribution editor.
• the wizard is quite slow (performance)

For the first issue we decided to implement the following:

1. we keep selection via tree structure
2. the checkbox uses triple state: a. checked, if, and only if, all subareas, and their subareas are fully included
   • undefined, if, some subareas are checked, but not all (including recursive subareas
   • not checked, if no of the subareas is checked or in "undefinded" state it self
3. opening a node in the tree works via "triangle button"
4. click actions: double functionality is needed
   • select/deselect all subareas
   • select the given area (not including the subareas)
   • problem: we want to avoid right click menus or other double functionality handling modes (e.g. single click/double click) as they are maybe not intuitive
   • solution: to select/deselect the single area (without subareas) we add it to itself as child node at first position, without children
5. click action "select all subareas" will
   • open the for one more level
   • check the parent checkbox and all child checkboxes
   • check all grandchild checkboxes if expanded, however for all grand(grand) children the information needs to be stored that they are "checked"
   • opening also all grandchildren takes a lot of rendering time and is not necessary
6. click "deselect all" will
   • unckeck all child and grandchild areas
   • not change the expansion state of the tree

For performance improvement need something like a UuidAndTitleCache for trees (including the parent information). Loading this should be faster then current implementation but can still load the full vocabulary at once if voc is not extremely large. But maybe this already exists e.g. from taxon navigator DTO.

Open issues:

• triple state is not yet correctly propagated to vocabulary during initial load (checkbox always empty)
• deselection only propagates to next parent, but not to grandparent (e.g. if parent switches from checked to undefined and grandparent is also checked, it also needs to switch to undefined)
• clicking on a parent which is in "undefined" does not change its state but should (either going to checked or unchecked, because also all its children switch to this state