Keyboard and mouse malfunction

When I try to chat with my allies. For some reason my keyboard malfunctions and then my mouse is set to the chat mouse cursor so I can't even exit out of chat. I can move my mouse around but its not the game mode mouse its the chat mouse cursor. No buttons on my keyboard works except for windows and alt, ctl, dtl. I just sat there and couldnt move or do anything. I had to alt/ctl/dtl to close League and reboot it.

This seems to be happening occasionally to me. Anyone else with this issue.