EDIT: I noticed it happens to every form, however only when it is called in a specific event which is handled. The form is shown in the DownloadFileCompleted event of a webclient, and that's the only place I get this bug when showing it. When I make it appear anywhere else, it works fine. I've also tried making it call a method but if it's linked to being shown with this event at all it gives me the bug. Any ideas? It's strange...