In spread mode, nothing indicates which window is selected

To reproduce the bug
1,Open multiple windows of any application
2,Trigger spread mode by pressing Super +W
You can select the preview with your keyboard, but there is no indication on the preview themselves that they are selected (unlike Expo mode where there is some sort of halo). You can only see the arrow on the launcher moving. The problem is that when you use your keyboard to select a preview, the keyboard input is interpreted as if you were selecting from the preview area and not from the launcher. Alright, I am not sure that this is very clear, so I am going to make an example with pictures.

In my first picture, the current window is chrome.
I pressed Super+W to activate spread mode (1, Chrome)
Then, I pressed down and it selected libreoffice (2. Libreoffice). Considering that the indication (the little white arrow on the right) as to which preview is selected is only displayed in the launcher, I would expect to be selecting thunderbird instead of libreoffice, since it's the icon underneath chrome in the launcher. Of course, if there were some sort of indications on the previews themselves, then this wouldn't be a problem.
Then I pressed right and it selected Thunderbird (3. Thunderbird) and the white arrow went up in the launcher.

It is a confusing behavior.