Windows 10 and client bug after opening LOL client after boot up

I'm currently running the LOL Legacy client (v. 7.4.17_02_16_18_30) and every time I open the client for the first time, I can't right click in the client and in Windows 10. The highlight function with the mouse in Windiws 10 is also bugged. The bug fixes itself after I play a game, and everything works fine in the client and on Windows 10, but it's still annoying.

P.S. I tried uninstalling LOL and reinstalling it but, the bug is still there.