There's an explorer.exe restarter utility from Windows Club I use for that, but there's one (or used to be) from NirSoft also.
T-Clock can do that too
If you Ctrl+Right-Click
it. Though it can be pretty slow as explorer sometimes hates to quit properly...
When did you move to Windows 10?
What did you use to capture the "screenshot"?
T-Clock seems to be correctly positioned, but there's this "black" rectangle, correct? The "Notifications" button is visible right next to it?
Also, what happens when you click on either the "black" rectangle or the visible part of T-Clock?
How does the mouse-over look, will it also clip where the rectangle is?
Ever tried to Right-Click
T-Clock and use "Refresh T-Clock"?
Restarting T-Clock or the Explorer (eg. through the way mentioned above)
should "fix" it without requiring to reboot.