Question: So whenever I try to click a button in the menu option in firefox with my mouse it won't respond. I tried to reinstall firefox but it didn't help. The menu button is located on the top right side of firefox.

Answer: 
Go to this website
<https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings>

and select the button saying refresh firefox:

> 
> 1. Click this Refresh Firefox button directly, if you are viewing this
>  page in Firefox. **This won't work if you are using a different browser
>  or on a mobile device**. 
> 
> 
> 	* You can also find a Refresh Firefox button at
> 	 the top of the Firefox about:support Troubleshooting Information page.
> 2. To continue, click Refresh Firefox in the confirmation window that
>  opens.
> 3. Firefox will close to refresh itself. When finished, a window
>  will list your imported information. Click Finish and Firefox will
>  open.
> 
> 
>
In my case, refreshing Firefox didn't work. What worked for me was to turn KWin compositing on (which I didn't know I had deactivated). That can be achieved by pressing `Shift`+`Alt`+`F12`