For Windows 10, Firefox 45.3.0 and Thunderbird 45.2:
I prefer using only 1 click to restore FF from systray. This works. But after some clicks / a few hours all icons in systray are blocked and can not be used further. Only 2 functions on right click are o.k.: restore all and shut down. Valid for all icons.
The problem is o.k. when I choose 2-clicks again. After this I can come back to 1-click.
For Windows 10, Firefox 45.3.0 and Thunderbird 45.2:
I prefer using only 1 click to restore FF from systray. This works. But after some clicks / a few hours all icons in systray are blocked and can not be used further. Only 2 functions on right click are o.k.: restore all and shut down. Valid for all icons. The problem is o.k. when I choose 2-clicks again. After this I can come back to 1-click.