I met a bug in operation the threshold button. It can’t be maximized.
I can’t make any changes for the value the of the threshold as is shown in the figure.
I don’t think that the Threshold window is supposed to be maximized.
If the issue is, that you can’t see the window, resetting your ImageJ/Fiji configuration should help. You can do that via Edit > Options > Reset, which requires a restart of ImageJ/Fiji. After that, you should be able to select the Threshold window again.
Really thank you very much. After reset, it is OK. I am able to select the threshold window now.