Steps to reproduce:
1. Create an ADG with variableRowHeight="true" with a renderer for it's child that displays somthing, see attached project.
2. Open a row
3. Notice the gridlines during opening
As the item opens, the gridlines show up on top as the renderer appears.
The renderer should show up on top of the gridlines so the gridlines aren't visible during opening.
Workaround (if any):
You can override drawHorizontalLine() to draw lines for items that aren't affected by the opening, thus creating a gap for the renderer to slide in, but it doesn't solve the vertical line issue.