TreeNode $$treeLevel logic is wrong

[ERobishaw]

If you want
A
....A.1
....A.2
....A.3
B
....B.1
....B.2
C
D
E

there is currently no way to inform the grid that C above does not have, and will never have children, and should not be a row-header.

Currently, the only way to ensure an item is not a row header is to set the $$treeLevel = undefined.
*This allows the following to pass:
*{'ui-grid-tree-header-row': row.treeLevel > -1}

However...
The problem with this is row C above will always be bolded.
B.2 has $$treeLevel = undefined, is a child of B, so it's OK
C has $$treeLevel = null, which makes it correctly not a child of B, BUT, internally, it gets wrongly assigned to row.treeLevel =1, or something... actually not sure how it's passing the test.

See Plunker Demo
In this example, "Morgan Sanford", row 45, should not be bold, it has no children.
And, setting "Toggle Expand No Children" only partly helps, because the row is still bolded.

[ERobishaw]

Found a quick fix:
set entity.$$treeLevel = -1 for all child-less entities.
Then, fix the following code:
*ui.grid.js, *
finaliseAggregations: function( row ){ if ( row == null || typeof(row.treeNode.aggregations) === 'undefined' ){ return; }
...

Added the if (row == null) check.

[tringuyenminh92]

i just quickly observed, but you could use cellTemplate to customize row header of records which has no children.

[zamb3zi]

This still doesn't work if there are one or more $$treeLevel === -1 rows at the start of the list. In createTree this causes the initial currentLevel of -1 to be decremented to -2 which leads to major problems.

A workaround is to make sure the top level rows at the start of the list have $$treeLevel === undefined and subsequent top-level rows have $$treeLevel === -1.