Accidentally disabled highlighting functionality with mouse

On several different occasions, I've made a typing error when using the alt ++ shortcut and I accidentally disabled highlighting with my mouse on all scripts on my R Studio session. It is beyond frustrating and the only way to restore highlighting with my mouse is by restarting my R and manually typing code from any previous R file that I had this issue in. It doesn't seem that using the same shortcut deactivates this as I've tried virtually every combination of neighboring keys.