Location not working for negative values, gets pushed to 0

Hi, I am trialling this and so far it's awesome. Just found one thing though trying to render HTML into a custom List Box and sometimes (for items at the top) painting needs to start at a location with a -Y for a partially drawn list item. I believe that I have found the problem and here is my fix, so far it seems OK (the Demo still looks all good).

In Layout cells there are some calls to Math.Max where the 2nd param is 0, it should be the existing Location value.

private void LayoutCells(RGraphics g)
{
double startx = Math.Max(_tableBox.ClientLeft + GetHorizontalSpacing(), _tableBox.Location.X);
double starty = Math.Max(_tableBox.ClientTop + GetVerticalSpacing(), _tableBox.Location.Y);
....
}

在 C# 原始碼中找到 LayoutCells 方法，並檢查目前與 0 比較的 Math.Max 呼叫。使用 Y 位置為負的部分繪製項目重現渲染，然後確認在保留表格框位置後，版面配置和現有的 Demo 仍能正確渲染。

由索引模型根據 Issue 內容生成。