Product and version: FileMaker 184.108.40.206 (Advanced)
OS and version: macOS 10.13.4
Hardware: 2016 15" MBP
Description: I've had both the Inspector and Field/Object sidebar fail to draw. The area remained blank. Switching to Browse and back didn't restore the window, nor did closing and opening the sidebars.
How to replicate: I've not been able to replicated it on demand, it just seems to happen. I've had it happen 2-3 times today.
Workaround (if any): Only way I've found to recover is to restart FileMaker