Letter 'c' is randomly inputted by dragging mouse on Mac I'm running Windows 8.1 on Parallels 10.4.0 for Mac. My issue is that every time I double click my mouse there is a 'c' character randomly inputted, which is very annoying. There is a solution from this link talking about the same issue, but I am unable to get this to work.

Has anyone ever had the same problem?

[Update] I found that the same issue exists when I use mathematica on OS X. When I drag click and drag the mouse, there will be an 'c' inputted. I doubt that it may be some software from OS X that caused the problem...
This was caused by a dictionary app called Youdao. I solved it by disabling the features named "Screen Translation 屏幕取词" &amp; "Selected Translation 划词翻译" of YoudaoDict.