Steam Achivements activate, but don't show the little Achivement icon popping up.

I've activated and fixed achievements, it works well and triggers the sound and everything when I unlock said achievement, but the problem is I can't see the popup.

Any idea how to make sure it shows up? It does show up when I trigger Steam overlay, but that also shows the entire rest of the steam overlay.

Edit: I'm using Webview.