'Frosted Glass' Effect behind Settings Gear Broken

[Avakining]

Describe the bug
When hovering over the settings gear (when settings is open), the frosted glass changed after a moment.

To Reproduce
Steps to reproduce the behavior:

1. Open Bonjourr settings
2. Move the mouse off of the settings gear
3. Move the mouse back onto the settings gear
4. See the frosted glass background of the gear icon change abruptly after a moment

Expected behavior
The frosted glass background fades in and remains unchanged until removing the mouse

Screenshots
https://github.com/victrme/Bonjourr/assets/25210618/47906d98-9218-4b9e-a47f-91ca98d501f4

Device (please complete the following information):

• OS: macOS 14.1.1
• Browser Firefox 120.0
• Version 1.18.3

[victrme]

I finally found how to reproduce the bug, "hide settings icon" has to be enabled ! The bad news is that it is not fixable as far as I know...

For the blur effect to work, the element needs to be at 100% opacity. Which means that the blur effect only triggers at the end of the opacity transition.

If there is an easy fix somewhere, I'll gladly fix it, but for now it is going to stay like this !