Can't use % in shortcuts?

Software version?

I'm using version 2019.1.3 for Mac - Just ran all updates to make sure I wasn't behind on anything.

What am I trying to do?

I want to make a shortcut that allows me to press (first stroke) Ctrl+b (second stroke) % to split vertically. 

What do I do?

I do this by going to Preferences > Keymap > search for "split vertically" > Right click > Add keyboard shortcut and then enter Ctrl+b in the firsts box and then add a checkmark to "Second stroke" and try to enter % in that box. I'm on a danish keyboard, so that would be shift + 5 

What do I expect to happen?

I expect PhpStorm to accept % as a valid second stroke

What actually happens?

Nothing. PhpStorm does not accept % as a valid shortcut. The field is left empty. 

Anything else?

When trying to use % in any shortcut (first or second stroke; doesn't matter), the % is completely ignored.
All of my other symbols (shift + 1 through 9) works as the should. 

It's not my % that is not working. I'm using the Idea Vim plugin and the % shortcut to jump matching brackets works just fine. 

I have tried disabling the Idea Vim plugin to make sure that the configs do not clash, but with no luck. 

Any thoughts on this issue?