Try:
1. Clear Firefox's Cache
Use Ctrl+Shift+r to reload the page fresh from the server.
If that doesn't help:

2. Clear Firefox's Cache Completely
orange Firefox button or Tools menu > Options > Advanced
On the Network mini-tab > Cached Web Content : "Clear Now"
Then try reload the page and check it again.

Unfortunately that didn't help. I also checked using Firefox Aurora 19.0a2 and the problem is still there. Nothing happens when clicking on the select box (it is not possible to see the different options anymore)..

Could your provide the exact link and screenshot of that.
https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem?esab=a&s=screenshot&r=0&as=s#os=win7&browser=fx16

http://proteomics.bmc.lu.se/proteios/app But you need to login to access the specific page: user:course1 pass:guest Then click 'course one' under Projects Then select from the Menu: 'Course One'->Reports->Hits Then click 'Table Options' in the top right corner of the table.

The check boxes work, but the selects need a special treatment for me on Linux.

It works if I right-click the selector arrow and after that left-clicking works for only that selector.
Dragging the scroll bar thumb moves that window, but the scroll buttons and the mouse wheel work.

That select box trick worked fine on Mac, but not on Windows. On Windows the check boxes work fine, as does moving the window. But there is no reaction when left- or rightclicking in any combination on the selector arrows or in the select boxes, as far as I can see.

All boxes and selectors work if I (temporarily) disable JavaScript after having opened the 'Table Options' window.
That works with a Linux Firefox version and a Windows version that runs under Wine.
So that script needs an update to fix the dragging issue.

It also doesn't work with Google Chrome.