Partition border not showing when changing background colour

[Stefanie]

I have an annoying issue for which I haven't been able to find a solution.  If I create a partition on an activity diagram using the default colours, it shows a border. However, as soon as I change the background colour to something else, the border disappears and only the line between the heading text and the body of the partition remains.  The only way to get the border back is to reset the local element appearance.  I have tried changing the line colour, but that does not help.  The only potential workaround I have is to create a boundary and place this around the partition, but I'm thinking this shouldn't be necessary - there should be a way to have a partition border in a contrasting colour to the partition background.