hello, can you try to replicate this behaviour when you launch firefox in safe mode once? if not, maybe an addon is interfering here...

Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

If I go to a site where I have to complete say my year month and day of birth from a drop down selection, I click to make a selection and instead of making my selection, this search list box opens up and wont let me make my selection

Can you attach a screenshot?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

Use a compressed image type like PNG or JPG to save the screenshot.