In xterm, in vim or other applications that can use the mouse in xterm, I used to be able to hold the Shift key to bypass that mouse button handling and do normal X selection.

With the latest update to xterm version 361 on Debian, that no longer works. In vim, Shift+LeftButton now seems to scroll down instead. After I enter printf '\e[?1000h', I see that Shift+LeftButton sends something like \e[M$xy instead.

How do I revert to the old behaviour? Or what would be an alternative way to do normal X mouse selection in vim (or other applications that enable the mouse protocol)?