Sorry to hear you are having issues. The blackbar does not appear on my system. Need to know more.
1) Windowblinds version installed.
2) The black bar only happen on specific theme or any theme?
3) The black bar appear on Dark and light Windows 10 colors theme?
4) Does restart the system help the issue?
And on Chrome not skinned properly on Windowblinds : It is known issue once again, you can refer to these thread discussing on it : https://forums.stardock.com/494835
Stardock Community Assistant.