My control key doesn't work, how do I fix it?

I have the same problem in gnome while running VMWare & I fix it by running the following:

setxkbmap

Use

 xev | grep -i keyrelease -A5

and press right ctrl to find its key code. Let's say it is 105, as on my keyboard. Then see what

xmodmap -pke | grep 105

tells us. It should be something like that:

keycode 105 = Control_R NoSymbol Control_R NoSymbol Control_R

If it isn't, you can change it with:

xmodmap -e 'keycode 105 = Control_R NoSymbol Control_R NoSymbol Control_R'

See whether it works now. If so, put this line into a script and add the script to your startup applications.

You probably need to fix your modifier mappings.

Do a

 xmodmap -pke > my.xmodmap

Use xev to check the scancodes of your control keys, and make sure they're set correctly in that file.

e.g. for me:

 ...
 keycode  37 = Control_L NoSymbol Control_L NoSymbol Control_L
 ...
 keycode 117 = Control_R NoSymbol Control_R NoSymbol Control_R
 ...

At the end of this file, add:

 clear Control
 add Control = Control_L Control_R

(btw, you can see your modifiers by running 'xmodmap' with no arguments.)

Then feed-back the modified mapping file:

 xmodmap my.xmodmap

I had the same issue running GNOME Shell; it was most obvious running mono apps and some games (such as Kerbal Space Program, which uses the left Ctrl).

I resolved it using GNOME tweak tool; under Keyboard & Mouse make sure "Show location of pointer" is disabled.

Had the same issue, went to the GNOME tweak tool; under Keyboard & Mouse make sure "Emacs Input" is disabled.