Tray icon is very small on KDE
v0.6.1 Kububtu 16.04 KDE 5.8.9
See screenshot below:

Works good on Kubuntu 18.04
Thanx for the info. Need to install Kubuntu 16.04 tonight.
Somehow the GtkStatusIcon is not handled correctly by the systray in 16.04. Please use the appindicator version for now and install the libappindicator library. Be aware that the appindicator version has no left click (show/hide) action on the icon. Only a menu action.
sudo apt install libindicator1
And restart Thunderbird.
@Ximi1970 Is it possible to implement mouse scroll on appindicator version?
By the way, I have to install libappindicator3-1 on KDE 18.04.
I am sorry to say new items or bugs are no priority atm. The add-on is not working anymore for Thunderbird 61+. It crashes Thunderbird. And I cannot find the problem....
Two things on that:
- If one wants to use the left mouse button for minimizing and reopening Thunderbird in KDE you have to disable the appindicator setting.
- I managed it to get the icon bigger by using a different icon. I used this one:
/usr/lib/thunderbird/chrome/icons/default/default256.pngthough it looks pixelized:
But this is not an issue for me.
@Ximi1970 Thanks soooooo much for updating the plugin, I already tried some other mail clients because I was so annoyed that minimize didn't work in TB 60 anymore...
Works good on Kubuntu 19.04