Unfortunately, this is what codemirror (because of Sublime) uses to select a rectangle (with multiple cursors). So, we need to at least make it so there is some other way to select a rectangle. I doubt the codemirror project would care, so probably this should just be a change in cocalc.
There's also no way to select a rectangular region on ipad either... so it would be cool if the fix for this also would work there. I don't know.
This is documentation that web apps can't use alt-click: https://productforums.google.com/forum/#!topic/chromebook-central/s6dDS-PNXI4
Unfortunately, this is what codemirror (because of Sublime) uses to select a rectangle (with multiple cursors). So, we need to at least make it so there is some other way to select a rectangle. I doubt the codemirror project would care, so probably this should just be a change in cocalc.
There's also no way to select a rectangular region on ipad either... so it would be cool if the fix for this also would work there. I don't know.