I have an entity Menu with field parent which is self referencing, so I can set up a tree like menu for my project. On the other hand I have a Property entity wich can be assigned to multiple menus. For the property edit and create view I need a multiple select box, where the structure/tree of the menu is displayed.
I managed to display the tree, but something is not working so that it is not possible to store the data or it is also not selected in the select box.
I can provide you the Menu and Property class, as well the MenuType and PropertyType for forms - I'd like you to create the possibility add a tree like multiple select box to the PropertyType with menus.