Hi.
It's a pity, but your script doesn't properly work - every time shows me the following message "Google token initialized failed, use youdao translator instead. Please contact the author to fix this problem."
Could you, please, fix it?
Thank you in advance.

Here is the log:
Uncaught TypeError: $(...) is null
googleTranslate moz-extension://b88958d4-f3a8-4e73-92e1-06bcbef443b8/userscripts/Google select text translator.user.js?id=d8763ffe-3e26-4a72-85d8-8f62595f8733:984
tms_d8763ffe_3e26_4a72_85d8_8f62595f8733 moz-extension://b88958d4-f3a8-4e73-92e1-06bcbef443b8/userscripts/Google select text translator.user.js?id=d8763ffe-3e26-4a72-85d8-8f62595f8733:247
T eval:3
moz-extension://b88958d4-f3a8-4e73-92e1-06bcbef443b8/userscripts/Google select text translator.user.js?id=d8763ffe-3e26-4a72-85d8-8f62595f8733:1
moz-extension://b88958d4-f3a8-4e73-92e1-06bcbef443b8/userscripts/Google select text translator.user.js?id=d8763ffe-3e26-4a72-85d8-8f62595f8733:1
moz-extension://b88958d4-f3a8-4e73-92e1-06bcbef443b8/userscripts/Google select text translator.user.js?id=d8763ffe-3e26-4a72-85d8-8f62595f8733:2530
moz-extension://b88958d4-f3a8-4e73-92e1-06bcbef443b8/userscripts/Google select text translator.user.js?id=d8763ffe-3e26-4a72-85d8-8f62595f8733:2532
T eval:3
N eval:2
E_u eval:3
Ka eval line 1 > Function:61
create eval line 1 > Function:73
L eval line 1 > Function:12
setTimeout handler*F_a/T Function:12
runListeners eval line 1 > Function:12
anonymous eval line 1 > Function:74
Aa eval:11

Sorry. Since the token value just stored in my browser storage, I didn't notice the function for fetch google token was ineffectiveness anymore. Until I reset my PC, then I found this issue.
Now, I'd been fixed it.
Just update to version v4.10.
Hope you enjoy it.

Thank you! It works now like a charm :)
Could you, please, add selection of the target language to translate to to the main window, e.g. like in the attached screenshot. It'd be best if it'll have favorite languages on the top of the list.

PS. Where could I make a donation to you? :)

PS2. Noticed one issue: Despite the option "Enable real-time selection translating mode (Otherwise click an icon to translate)" is selected after loading a site's page at first use of the script I need to click on the popup icon for the main window to appear after this all subsequent times the main window appears instantly while selecting text.