What is a woman's awrah in front of another woman? And why do some shaykhs not permit wearing short dresses that cover the awrah in front of women if the awrah is from the navel to the knee, with evidence?

If some scholars have issued fatwas prohibiting the wearing of short dresses in front of women, it might be for reasons other than the issue of covering the 'awrah. For instance, the dress might be tight, revealing the size of the 'awrah, or it might involve imitating disbelieving and immoral women, citing the hadith: "Whoever imitates a people is one of them."