I just read an interesting psak by Rav Elashiv regarding the upcoming three day holiday of Rosh Hashana on Thursday and Friday immediately followed by shabbos.

It is common in Haredi communities in Israel that men wear a special "frock" for Yom Tov. As a matter of fact, I always find that very weird. I am used to frocks being the dress code of Rosh Yeshivas and great Rabbis, yet we see young newly married men wearing frocks when it is yom tov. Be that as it may be, the frock is worn among the general public in haredi communities.

Rav Elyashiv declared that the special frock should, in cases of three days yom tov, be worn not just on Yom Tov, as is the custom. Rather the frock wearer should continue wearing the frock even on the third day, being shabbos (the day that the frock is generally not worn).

The reasoning behind this psak is that by wearing the frock for the holiday and then immdeiately removing it and not wearing it for shabbos is, in a sense, disgracing and shaming the shabbos. You are somehow saying that shabbos is less worthy. In order to avoid that, one should continue wearing the frock on the third day being shabbos.

Note: this would not mean that the frock should be worn on a regular shabbos in order to avoid shaming the shabbos by treating it less than a holiday. it is only when the days are continuous that we are concerned about this.

I would compare this psak to the Yekkish minhag of tallis wearing. When the Torah is read during Minha, for example on Shabbos afternoon, Yekkes (among other communities as well) will don the tallis when getting the aliyah to the Torah.

What is unique about the Yekke community is that after the person completes his alyah, he will generally not remove his tallis. He will continue wearing it and wear it through the subsequent tefilla, only removing it after kedusha. The reason for this, as I understand it, is that it is disrespectful to don the tallis for the aliyah (which is really kavod hatzibbur) and then remove it for the tefilla. It is, in a sense, disgracing the tefilla and saying the tefilla is less important. To show the tefilla is not less important, we keep the tallis on until after we have davened shmoneh esrei.

I like this psak of Rav Elyshaiv. I think it makes sense and if I wore a frock, which I do not, I would wear it on shabbos as well after yom tov.

I wonder if this applies to the kittel I wear though.

Most men wear the kittel only on Yom Kippur, I wear the kittel on Rosh Hashana as well. The kittel is worn not so much as kavod for the holiday (which is why the frock is worn), but to resemble angelic behavior and purity. So to not wear it on shabbos should not be disgracing the shabbos and should not be considered treating it any less than the holiday.