Tooltips for Inspector items frequently don't appear, until the mouse is clicked on them, and don't disappear after moving the mouse away.

Steps to reproduce:
1) Open any project.
2) Go to Player Settings.
3) Hover over any field that should show tooltips (GPU Skinning for example).

The tooltip usually doesn't appear immediately, the field name has to be clicked first. When the tooltip appears, moving the mouse cursor away doesn't make it disappear, until the mouse is clicked somewhere else.
This doesn't occur on macOS and Windows.

Reproduced on:
2017.1.0b1 (trunk), 5.6.0f3, 5.3.6f1