Difficulties- Part 2

So the other major difficulties I encountered with this website is the fact that when I press preview in say Firefox or Google Chrome, sometimes the drop-down menu doesn't align. For example;

So I tried to search on google as to why this would happen as it doesn't happen all the time, just sometimes when I open it up, and it said to reload the page so once reloaded, the page is back to normal and everything is aligned which is odd. I still haven't found a solution for that other than to reload the page if it does do that, as as I mentioned before, it sometimes happens, sometimes it doesn't which is rather odd.