Hello. I have a problem with typing Polish characters directly from the keyboard in a text editor (ą, ę, ś, ć, ż, ł, ń, ó). At the moment, the only solution is to copy these characters from the document to the editor.
Hello! Could you please let us know which English keyboard letters these characters correspond to? This way we could test and fix it. Thank you for your cooperation!
I give shortcuts like these letters on the English keyboard:
ą (right alt + a), ę (right alt + e), ś (right alt + s), ć (right alt + c), ż (right alt + z), ź (right alt + x), ł (right alt + l), ń (right alt + n), ó (right alt + o)
The same applies to large characters.
Ą (right alt + A), Ę (right alt + E), Ś (right alt + S), Ć (right alt + C), Ż (right alt + Z), Ź (right alt + X), Ł (right alt + L), Ń (right alt + N), Ó (right alt + O)
Thank you for the prompt reply! We’ll test and fix it!
in the last version of 4.0.1 I still can not enter Polish characters in the text content. 
We heard you. This feature will appear in the next release.
great, thanks a lot. 
Not only an issue with Polish characters, but for all characters (in any language I suspect) that are mapped to AltGr + key.
For instance on a French layout keyboard: AltGr + E for the euro-symbol or AltGr + 2 for the @ symbol.