How to get numpad arrows working (Ubuntu)?

Pressing any of the normal arrow keys on the numeric keypad (numlock OFF), are simply ignored by GoLand's editor.

I can use those same keys in any dialogs - including ironically enough - the keyboard mapper under settings.

HOWEVER - that does zip - because pressing numpad left-arrow (aka 4) shows "LEFT" in the keyboard mapper - which it thinks is already mapped to 'left' - and the non-keypad left is mapped correctly.

So the keymapper cannot distinguish the key - and the editor cannot see the key.

This makes it entirely impossible to use the keypad as normal, which is a show-stopper for me.

I love the intellisense here - but I must have my numpad as arrow keys (including their ctrl and shift variants) or I simply grind to a stand still.

This is Ubuntu 18.04 LS - up to date.
VS Code works properly and allows me to remap those same keys - which it sees properly as "numpad 4" and so on - rather than as invisible or indistinguishable from the dedicated left-arrow key.

Is there some way to get this to work?