Pull up a grid  over descendants spans of the according span.
1. Refactor a logic of renderer.
2. Add new function 'domSelector.grid.get'.
3. A function 'indexPositionXxx' is changed to 'positionUtils' that is called at use.
4. Rmove a function 'gridMouseHover' that is not work.
5. Tuning redraw that run at end of window-resize.
6. Fix comments.
Bug fix: A dialog cannot store its state. It is initiated at open each.