Almost two weeks, and nobody answers to our questions! It's very frustrating here.
I think it's because it's not really a big issue, mainly an annoyance. It is only present when you group tasks by workspace. Depending on your usage, grouping by workspace is not a very useful grouping. Our install has over 1000 workspaces so this grouping is pretty useless to find tasks.
Other than the annoyance of it being there - how does this impact the workings of FO?
Have you posted this as a bug on the bug tracker? That is the better way to get information to the developers than this forum, I have found. They tend to come here only every few weeks.