Created some free sites to play online versions of retro MS games like Minesweeper, Solitaire and others such as Sudoku & Tic Tac Toe. I learned about Cloudflare's Pages at same time to host all the code at no cost.
Clicking both mouse buttons on Minesweeper to reveal all the squares around a square doesn't work for me (Firefox on Linux).
I don't know if it's a browser issue (browser restrictions on JS altering right click behavior), a runtime issue, or maybe you're using a very old version of Minesweeper that doesn't support this function? (I know the Windows 95 version supports it)