[Regression] Outline on hover isn't working anymore

[adriengivry]

Description
Following the merge of #277, hovering an object in the scene view doesn't reveal an outline for it.

To Reproduce
Steps to reproduce the behavior:

1. Open a new project
2. Create a cube actor
3. Hover the cube with your mouse cursor in the scene view
4. Notice that there is no outline around the cube

Expected behavior
An outline should be displayed when hovering an actor

Screenshots