Create files on collapsed folders (#2085)

[jbalsas]

This is a possible fix for #2085 by waiting on the open_node.jstree event before trying to create a new node.

It looks like we're hitting a strange race condition in jsquery.jstree.js which appears when the node we want to open hasn't been loaded yet.

In that case, open_node triggers a load_node in line 640.

632  open_node  : function (obj, callback, skip_animation) {
         [...]
638      if(!this._is_loaded(obj)) {
639          obj.children("a").addClass("jstree-loading");
640          this.load_node(obj, function () { t.open_node(obj, callback, skip_animation); }, callback);
641      }

Almost at the same time, a different load_node is triggered from the CRRM create through create_node in line 734

726  create_node    : function (obj, position, js, callback, is_loaded) {
         [...]
733      if(obj !== -1 && !obj.length) { return false; }
734      if(!is_loaded && !this._is_loaded(obj)) { this.load_node(obj, function () { this.create_node(obj, position, js, callback, true); }); return false; }
735
736      this.__rollback();

Not digging much further, if the second load_node gets called because the first one is not completed, then create_node is not called again as expected and nothing gets created. This can be tested by adding a breakpoint in line 733. Doing that, the first load_node always finishes and the function completes ok.

By waiting to the open_node event, we're making sure we always step into create_node once the node is already loaded.

UPDATE Just to confirm, the load_node_json call just returns without doing nothing if the node is already being loaded, which causes the callback to create_node to get dropped without ever being called. Also, this check seems to have been removed in the v1.0 branch (https://github.com/vakata/jstree/blob/v.1.0/src/jstree.json.js)

[gruehle]

Works great! Thanks for the fix.