#1000 MinMaxCategoryRenderer not drawing all lines

[Uri Moszkowicz]

The MinMaxCategoryRenderer doesn't draw the min-max line for categories where the number of rows is less than the row count. A simple fix is to change drawItem() so that it computes the last non-null row value for each column. A speedier fix might be for Dataset to cache this value or better yet for Dataset to keep a separate rowcount for each column, though this might require rewriting a bunch of other code. Probably the first fix is sufficient.

For those using MinMaxCategoryRenderer already, a simple workaround is to repeat the last point until the number of points is symmetric across all categories.