Does make sense using "Enhance Contrast" before setting the threshold?

I’ve been using ImageJ to anayze cell images. I’ve found usefull the command “Enhance Contrast” to make the picture clearer before setting the threshold and procede with the analysis. However I’ve recently noticed that when I set the threshold the effect of the contrast is eliminated. Now I am not able to say wheather it is a normal behavour of the software or not.
If someone could help me solving this simple problem, it would be great.

You need to Apply LUT so that the pixels in the image change. If not, you are only changing the LUT. Unless you hit the equalize/normalize options, that should do it too but it would change the enhance contrast you are doing.