This is an obscure bug, triggered when you display the form with the Windows toolbar overlapping your StatusStrip. Moving the window away from the toolbar doesn't get the ToolStripItems on the status strip repainted properly. You'll find a bit of background in this forum post. There was a weak promise for a future fix for it, no idea if that ever happened. Probably not if you are running this on Win7.
You'll need to pay more attention to the position of the window, making sure that parts of it don't disappear underneath the toolbar. In general something you'd always consider, extra important as long as this bug doesn't get fixed. If you don't want to nail down the startup position (you ought to, users tend to like a window getting redisplayed where they last moved it) then simply change the form's StartPosition property to "CenterScreen".
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