TreeGrid extension uses all grid events but there are two additional ones. The following purely TreeGrid events are available:

• onOpenStart Event - occurs after an item in the tree got the command to open/close, but before this item was opened/closed; also occurs for unclosable nodes and nodes without open/close functionality - in that case the result of the function will be ignored;
• onOpenEnd Event - occurs after an item in the tree got the command to open/close and related change in the structure was processed (that includes data loading in case of treegrid in dynamical loading mode).