Problems computing EXACT grid dimensions (HxW)

Hi All,

If I have a grid with 5 rows x 20px, and 3 columns x 100px, I'd expect the control size to be:
obj.setControlSize(300, 100);

If I set it this way, instead, scrollbars appear "eating" obviously a portion of the area.

If I increase both dimensions by (let's say) 10px, then what I get are extra pieces of the next column and row.

Where am I missing the point?

Diabolik