Right now you invoke block selection by entering a dedicated "Block Selection" mode. However it might be nice if you could additionally make a quick block-selection without having to enter and exit that mode by dreagging while holding down the alt key. This is the way you invoke block selection mode in various other text editors and platforms (e.g. Notepad++, VSCode, and all macOS apps with text fields).
*** Bug 423839 has been marked as a duplicate of this bug. ***
*** Bug 340778 has been marked as a duplicate of this bug. ***