Product feature dropdown not showing [PS 1.7.4.4 Backoffice ]

[Billy P.]

When I go into a product and try to add features, the dropdown menu on step 2 doesn't work.
Step 1 works as it should and I get all different, but when I want to choose value it can't.

I have tried to create a new feature but still get the same error.

Anyone who has had this problem or thinks they know a solution?

ps-error.pdf