"Focus with Tab Key" is not visible

[ss005]

To reproduce issue :

Open any window or any file manager.
Now press tab, tab, tab....
we cannot see which component is focused..

for example, in below image, if we press tab key, we cannot say whether "Help" button or "Close" button is focused.

Same issue happens if we open file manger and press - tab - tab ....
or in any case of pop windows like below,

It is difficult to see which button is focused.

It is working with other dark themes like with Adapta theme :

After pressing tab, "Cancel" button is focused.

Please ask if it is not clear.
Thanks in advance!

[joemaro]

This is a big issue, because it makes this wonderful theme not usable for people that hardly ever use the mouse. I'd love to use vertex, but it means that i have to grab the mouse quite often because i can't see which button is currently selected.

That said, many other themes have this issue as well.