Hi MATLAB,
You may use the drawing tool to create the rectangle, making sure you send
the rectangle to the back. This is somewhat problematic if you then zoom the
Gantt chart in or out.
The other method I prefer is to create a custom calendar (Tools> Change
Working Time...New). Select the days during the Winter months and mark those
as non-working.
Then in the Gantt chart, right click over the Gantt chart and select
Nonworking Time from the shortcut menu. Select the nonworking time from the
custom calendar.
Hope this helps. Let us know how you get along.
Julie