version 65.0.3299.0 (offical build) dev (64 bit)
Platform 10315.0.0（official build) dev-channel link 
Firmware Google_Link.2695.1.169


REPRO STEPS:
1.Enable #floating-virtual-keyboard
2.Focus on any inputbox
3.Click Menu list, select Floating Keyboard
  
Actual result: 
Keyboard flashes then display Screen flashes.