Disclaimer: I did some research for this question; I did not know all of this off the top of my head :P. Sources were found through the footnotes in Rabbi Ribiat's The 39 Melachos. It is forbidden to ...
Assuming one is inside an eruv which generally permits transferring between domains on Shabbat, may one use an umbrella on Shabbat? If not, why not? Follow-up question: What about other things that ...
According to Rabbi Dovid Ostroff Shlita The Rama in Hilchos Succah 626:3 says that one is permitted to open and shut hinged flaps that are used for covering the Succah when raining. The ...