[Bug 40696] New: Firefox doesn't always redraw its window completely

https://bugs.winehq.org/show_bug.cgi?id=40696

Bug ID: 40696
           Summary: Firefox doesn't always redraw its window completely
           Product: Wine
           Version: 1.9.6
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdi32
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 54574
  --> https://bugs.winehq.org/attachment.cgi?id=54574
Console log

I tested this on Firefox 46, but similar problems exist with previous versions.
Steps to reproduce the problem:

1. In clean Wine prefix install Firefox
2. Launch Firefox, close the "default browser" dialog and close extra tabs so
that only one remains
3. In the current tab go to youtube.com, wait till it loads completely
4. Press Ctrl+T to open a new tab
5. Start entering a URL, e.g. type the letter "g"
6. When suggestions dropdown opens, press Ctrl+W to close this tab
7. This gets you back to youtube page, but you see that only top part of the
page has actual youtube contents, while the bottom remains from New Tab page.

In some other cases just switching from one tab to another leads to nothing
being redrawn at all (even when trying to scroll) as though Firefox hung with
contents of previous tab, but going back to previous tab makes it redraw again.