I have an application that has a 3rd party tab strip (DotNetBar) across the top of a parent form in a WinForms application. The issue that is occurring is that when clicking on a tab to switch forms and then moving the mouse around the screen, the application behind the WinForms application begins to bleed through which is undesirable.
Now I have seen this behavior over 4 version now of the tab strip, hoping an update would fix the issue but I don't believe the tab strip is at fault.
My hypothesis is this, but please answer independently. The tab clicks have some intensive code processing occurring (database calls, screen load stuff, logic, etc.) when clicked. I'm wondering if the cause is that because all of this processing must be occurring on the UI thread, the WinForms application can't keep the main application Window refreshed (maybe?) and the background is bleeding through. I wonder if offloading the intensive work to a background thread, and allow the UI to refresh and continue separately would help.
I think I've seen similar behavior on poorly performing Windows Machines over the years, that's why I believe this issue is generic and not necessarily of the control (although I could be wrong on this).
My main generic question here is what could cause the application to bleed through the main foreground in a Windows Forms application?