Many people are familiar with the "Sabbath Mode Ovens" that the Star-K has helped design which one is allowed (according to R. Moshe Heinemann) to adjust on Yom Tov (not Shabbos, despite the name -- link).
The Yeshiva World is reporting that a number of leading authorities have prohibited the use of such ovens (link). Rabbis against the use of these ovens include: R. Yosef Shalom Elyashiv, R. Nissim Karelitz, R. Shmuel Wosner, R. Feivel Cohen and R. Yisroel Belsky.
From Wikipedia (link):
In more recent ovens, Sabbath mode will often feature the ability to adjust the temperature of the oven without any feedback to the operator of the oven. This is not relevant to the Sabbath, but is useful on holidays, when adjusting the heat is allowed, but changing a digital readout on the control panel is not, according to the prevailing Orthodox opinion and the minority Conservative view. With some Sabbath mode ovens that are controlled using a keypad to set the temperature, there is a random delay after a button is pressed before the temperature change takes place.