Gray Bar Taking up Half of Excel Window

I maintain some fairly hefty excel spreadsheets for a financial services firm. The sheets have plugins to real time stock prices via a DDE feed from a firm called Bloomberg. There are a number of macros that pull data via queries from an MS SQL Server database. There are also a number of different pivot tables that display all the data that comes in.

Here is the problem: some users will randomly experience a gray bar that takes up the left third of the excel window. This affects any other spreadsheets that open up in that session of excel. You can actually slide the windows in that session under or away from this gray bar. The gray bar is not resizable, and the only way to get rid of it is to completely kill the excel session.

The problem is usually triggered after a user hits a button that runs code that executes the query to MS SQL Server, and then some other cleaning and formatting of cells. Users may go weeks without seeing it before they get it again. Some users experience it, others don't.

For the most part, the users are on Windows 2000 Professional and Excel 2000. Others are on 2003.

Any help would be greatly appreciated.

I've had this problem intermittently for a year. It occurs seemingly at random and is incredibly irritating. I'm still no nearer establishing what causes it (despite mucking about with spy++ and trying to use win API functions to force it to shut), but at least now know how to get rid of it without having to shut down the whole process. The trick is to drag a toolbar over the offending grey bar - it should then go away again. I bring this up now because when I'd searched for it in the past I found several people seemed to have experienced the same problem, but no-one seemed to have a solution that worked for me.