Very annoying: cannot input a special character the usual way in SDL Trados Studio 2017 SR1

After upgrade, when using Polish keyboard, I cannot input the small l with stroke (unicode U+0142) the usual way (left alt + l), which is very annoying. Could someone help me out with it?
(It still works as a charm in all the other applications I use: outlook, word, excel, notepad, mozilla firefox etc.)

Thanks,

Piotr