Hi. I use the Firefox web browser. Since yesterday I have several problems with long lessons. I beleive that something is changed... if not, these problems could be caused by my Internet connection, which seems to be quite slow in the last few days.
I'll try to describe the problem:
1) I click on a word; 2) I click on I know the pen (so that the word becomes yellow); 3) I click on the next word too quickly; 4) I click on I know this words; 5) repeat the process at least one time
As a result, sometimes the words I wanted to become yellow will be marked as known, and vice versa. It can also happen that some words remain blue. So I have to use the system slowly, or it is unreliable.