xircon wrote:Must be a Mate problem. Works in Cinnamon (though I never knew it existed!).
It's not, now is it
I already commented it works fine just two comments up. Both on Linux Mint 13 MATE and on LMDE MATE, Pluma is happy to Ctrl+Shift+Left/Right select a whole word.
If you aren't on a virtual machine, perhaps you have installed something else that captures key presses? I don't know, like Compiz or Docky or something. Or possibly you have set a global keyboard shortcut. Check in Keyboard Shortcuts application that none of the shortcuts are set to Ctrl+Shift+Left/Right.
To rule out this being caused by such as I suggest, boot from the LMDE installation DVD/USB. Try Pluma from there. Type some words and try to Ctrl+Shift+Left/Right select them. If you can, this means something you installed or configured on your LMDE installation is causing a conflict. If it also doesn't work from the LMDE installation DVD/USB, I'd suspect a hardware failure in your keyboard.