How to select a column of text in Sublime Text 3?

Although the use of Ctrl+Alt+↑ and Ctrl+Alt+↓ are currently suggested for column selection in Sublime Text 3 for Linux,

they don't work. Instead, one has to use alt+shift and the appropriate arrow key according to this technical support response.

To get these keybindings to work in Lubuntu 18.04, I commented out the following lines in ~/.config/openbox/lubuntu-rc.xml:

<keybind key="S-A-Left">
  <action name="SendToDesktop">
    <to>left</to>
    <wrap>no</wrap>
  </action>
</keybind>
<keybind key="S-A-Right">
  <action name="SendToDesktop">
    <to>right</to>
    <wrap>no</wrap>
  </action>
</keybind>
<keybind key="S-A-Up">
  <action name="SendToDesktop">
    <to>up</to>
    <wrap>no</wrap>
  </action>
</keybind>
<keybind key="S-A-Down">
  <action name="SendToDesktop">
    <to>down</to>
    <wrap>no</wrap>
  </action>
</keybind>

saved the file, ran openbox --reconfigure and now I can use Shift+Alt together with the appropriate arrow keys to select a column of text in Sublime Text v 3.2.1.

Note: openbox --reconfigure does two things:

• It parses your rc.xml or menu.xml files for errors and
• it "reloads" the edited (and saved) file so you don't have to log out and log back in for the changes to take effect.

Note: If you have LXDE the file to modify is ~/.config/openbox/lxde-rc.xml instead.