Group columns with spans

You can define a TreeListColumnSpan and add columns to this in order to group the columns. The spans and columns will be rendered like this:

A column can be assigned easily to a span by adding the span as param to the TreeListColumn's constructor. Columns that should not be grouped by a span are constructed with the grid as parameter:

TreeListColumnSpan span1 = new TreeListColumnSpan("Info", mailList);
TreeListColumnSpan span2 = new TreeListColumnSpan("Email addresses",
		mailList);

// define the columns
TreeListColumn colRowNum = new TreeListColumn(mailList);
colRowNum.setWidth(30);
colRowNum.setText("#");
colRowNum.setAllowReorder(false);

TreeListColumn colHeadline = new TreeListColumn(span1);
colHeadline.setWidth(150);
colHeadline.setText("Headline");

TreeListColumn colSize = new TreeListColumn(span1);
colSize.setWidth(75);
colSize.setText("Size");
        

Moving columns in spans

The columns that are grouped in spans can be dragged from spans into other spans and also dragged out of a span. See the following demo: