Grid with frozen column shows unnecessary scrollbar

I implemented a grid with a frozen column with ZK 6.5.1.1. A horizontal scrollbar is shown even if the window is big enough to show all columns. The scroll area width seems to be almost twice of the grid width. Below a demo zul file:Frozen ColumnColumn 1Column 2 How can I adjust the scroll area to the size of the grid? Without freezing a column everything works as expected.