a problem about flash back

Operating system: Mac OS Big Sur
Slicer version: slicer 4.11
Expected behavior: solution to flash back
Actual behavior: I can’t do anything when I import an external data, I click on any option in Slicer like Segement Editor and it flashes back, In addition, when selecting options such as Level tracing or Grow from Seeds during ROI delineation of DTI data, flash regression will also occur.

It’s not clear to me what you mean by ‘flash regression’. Maybe you can make a screen recording to show the issue?